**Process Specification for Automatic and** Machine Arc Welding of Steel
and Nickel Alloy Hardware

+-----------------------------------------------------------------------+
| **Engineering Directorate**                                           |
|                                                                       |
| **Structural Engineering Division**                                   |
|                                                                       |
| **February 2006**                                                     |
|                                                                       |
| ![](media/image1.png){width="1.3944444444444444in" height="1.15in"}   |
|                                                                       |
| National Aeronautics and                                              |
|                                                                       |
| Space Administration                                                  |
|                                                                       |
| **Lyndon B. Johnson Space Center**                                    |
|                                                                       |
| Houston, Texas                                                        |
+-----------------------------------------------------------------------+

**Process Specification for Automatic and Machine Arc Welding of Steel
and Nickel Alloy Hardware**

+------------------+---------------------------------+------+---------+
| **Prepared by    | ####                            |      |         |
| :**              |                                 |      |         |
+------------------+---------------------------------+------+---------+
|                  | Daniel J. Rybicki               |      | Date    |
|                  |                                 |      |         |
|                  | Materials and Processes         |      |         |
|                  | Branch/ES4                      |      |         |
+------------------+---------------------------------+------+---------+

+------------------+---------------------------------+------+---------+
| **Approved by:** | ####                            |      |         |
+------------------+---------------------------------+------+---------+
|                  | Bradley S. Files,               |      | Date    |
|                  |                                 |      |         |
|                  | Chief                           |      |         |
|                  |                                 |      |         |
|                  | Materials and Processes         |      |         |
|                  | Branch/ES4                      |      |         |
+------------------+---------------------------------+------+---------+

  ----------- --------------------------------------------- ---------------
  REVISIONS                                                 

  VERSION     DESCRIPTION                                   DATE

  Baseline    Original version                              6/1/95

  A           Formatting, changed process owner,            07/29/99
              elimination of subclasses and types, deleted  
              requirement for WIR, refers to ASTM specs     
              E1417 and E1742, refers to heat treat PRCs,   
              included and expanded acceptance criteria,    
              deleted section 8.2 on audits, rewrote        
              numerous sections for clarification.          

  B           Allow for flight and non flight hardware.     02/06/2004
              Numerous editorial corrections. Include       
              requirements for precision cleaned hardware   
              (ref. JPG 5332.1). Rewrite definitions for    
              weld classes. To match that of PRC-0005.      

  C           Correct 2 typographical errors where it was   02/16/2006
              found a reference to PRC-0005 and should be   
              PRC-0010. Changed reference to SOP-004.5 from 
              EM-004.5.                                     
  ----------- --------------------------------------------- ---------------

**1.0 [SCOPE]{.underline}**

This process specification provides the minimum requirements that govern
the automatic and machine arc welding of steel and nickel alloy
hardware. Procedural and quality assurance requirements are given. All
Detailed Process Instructions (DPI) and Weld Procedure Specifications
(WPS) used during welding shall satisfy the requirements of this process
specification and its applicable documents.

# **2.0 APPLICABILITY**

This specification applies to the automatic and machine arc welding of
carbon and alloy steels, stainless and corrosion resistant steel alloys,
and nickel alloy hardware fabricated under the authority of the
NASA/Johnson Space Center (JSC).

This process specification applies to arc welding of carbon and alloy
steels, stainless and corrosion resistant steel alloys, and nickel alloy
hardware that is fabricated under the authority of NASA/Johnson Space
Center (JSC) by any of the following types of welding processes:

a.  Gas tungsten arc welding (GTAW).

b.  Plasma Arc Welding (PAW).

The term "flight hardware" refers to any hardware used as a part of a
spacecraft, aircraft, or payload. The term "ground based hardware"
refers to any hardware made for facilities (buildings and related
accessories), ground support equipment, training and mockup mission
equipment, engineering prototype and development hardware, and test
equipment.

# **3.0 USAGE**

This process specification shall be invoked by including a note on the
applicable engineering drawing with the following general format which
specifies the PRC and weld class nomenclature:

**WELD AND INSPECT PER NASA/JSC PRC-0010, CLASS X.**

## To minimize fabrication costs by avoiding over-inspection and unnecessary rework/repair, individual welds, or components on a weldment shall be classified separate where possible. This can be accomplished by including a note on the engineering drawing with the general format shown below which specifies only the PRC nomenclature. The weld class shall then be indicated by either: 1) calling out the specific weld class with the welding symbol at the individual weld joints or, 2) by using specific flag notes with the welding symbol at the individual weld joints. Refer to Figure 3.0a and 3.0b below for examples of these methods.

**WELD AND INSPECT PER NASA/JSC PRC-0010. WELD CLASSES SHALL BE AS
INDICATED AT WELD LOCATION CALLOUTS.**

## 

## 

## 

## 

## 

## **3.1 WELD CLASSIFICATION**

Welds made using this specification shall be primarily classified in
accordance with the service conditions of the weldment. The \"Class\"
governs the extent to which quality assurance provisions are applied to
the weld joint.

Alternatively, individual welds, welded connections, or entire weldments
(for simplicity, the terms weld, welded connection, and weldment will be
used interchangably) may be classified by relating the weld to the
factor of safety used in the design. However, when classifying welds in
this manner, regardless of the factor of safety, adequate consideration
should be given to the severity of the service conditions (e.g., static
loading vs. dynamic loading, cyclic, vibration, fatigue, corrosive,
extreme temp, etc.), material characteristics (e.g., ductility,
toughness, etc.), and the potential consequences of weld failure.

Where conditions exist that make it difficult to choose between 2 weld
classes, then the more stringent of the 2 classes shall be applied.

Quality assurance provisions for all weld classes are detailed in
Section 7.0. Weld classes shall be chosen on the basis of the following
definitions:

a.  [Class A]{.underline} (Flight or non flight) --- Applies to welds in
    critical load bearing elements that are not fail-safe. Class A welds
    are typically used in primary load bearing connections. Failure of a
    Class A weld in service would be catastrophic and would result in
    the loss of life, system(s), control, or major components.
    Alternatively, if it is determined from appropriate engineering
    analyses that a weld has a Factor of Safety (FSuts) vs ultimate
    tensile strength of the calculated minimum weld throat cross section
    of \<2.0, it shall be designated as a Class A weld.

b.  [Class B]{.underline} (Flight or non flight) --- Applies to welds in
    load bearing elements that are fail-safe. Class B welds are
    typically used in secondary load bearing (i.e., shared load)
    connections. Failure of a Class B weld in service would reduce the
    overall efficiency of the system, but the loss of the system(s) or
    endangerment to personnel would not be expected. Alternatively, if
    it is determined from appropriate engineering analyses that a weld
    will have a FSuts of ≥2.0 and \<3.5, it may be designated as a Class
    B weld.

c.  [Class C]{.underline} (Flight or non flight) --- Applies to welds
    that are in minor load bearing elements that are fully contained
    where failure in service would have minor or no affect on the
    efficiency of a system and endangerment to personnel would not
    occur. Class C welds are typically used in secondary or tertiary
    load bearing (i.e., shared load) connections. Alternatively, if it
    is determined from appropriate engineering analyses that a weld will
    have a FSuts of ≥3.5 and \<5.0, it may be designated as a Class C
    weld.

In addition to the above definitions, the following requirements shall
also apply to weld classifications:

-   If any weld intersects or overlaps another weld of a higher
    classification, then the lower classed weld shall be automatically
    upgraded to the higher of the 2 weld classes and subjected to the
    appropriate quality assurance provisions.

-   If any weld falls within ½" of any higher classed weld, then it
    shall be automatically upgraded to the higher of the 2 weld classes
    and subjected to the appropriate quality assurance provisions.

## 

## **3.2 WORK INSTRUCTIONS**

Work instructions shall be generated for implementing this process
specification. The work instructions shall contain sufficient detail to
ensure that the manufacturing process produces consistent, repeatable
products that comply with this specification. At JSC, these work
instructions are approved as Detailed Process Instructions (DPIs) that
describe in a detailed, step-by-step format the required procedures,
equipment, and materials to be used for conducting a given process.

If this manufacturing process is to be performed by an outside vendor,
work instruction development shall be the responsibility of the vendor.
The contractor shall ensure that the work instructions meet the
requirements of this process specification.

## **3.3 DESIGN REQUIREMENTS**

a.  The design of welded joints (including weld sizes) shall utilize
    adequate engineering analysis methods (e.g., stress analysis,
    fracture mechanics/fracture control, etc.) to ensure that the
    resultant connection strength is capable of successfully
    transferring the maximum load expected to pass between the
    interconnecting members and meet the required factors of safety and
    design margins.

b.  All engineering drawings shall depict welded joints using the
    applicable symbols described in AWS A2.4.

c.  The engineering drawing shall specify any additional or alternate
    testing or inspection requirements. Where spot, intermittent, or
    other special inspection requirements are specified that deviate
    from those stated herein, it shall be detailed on the drawing as a
    note or by using the applicable symbology described in AWS A2.4. For
    Class A welds, alternate or reduced NDE requirements shall not be
    allowed.

d.  Class A welds are expected to be welds requiring full strength of
    the weld joint therefore, these welds shall be a groove design and
    full penetration wherever possible. The ability to successfully
    perform radiographic examination on these weld joints shall be
    considered during design.

e.  Class A welds which will be subjected to unusual or extreme service
    conditions (e.g., severe dynamic loading, cyclic, vibration, impact,
    corrosive, fatigue, extreme temp, etc.), shall be welded using a WPS
    qualified in accordance with AWS B2.1 "Special Test Weldments." This
    requirement shall be noted on the engineering drawing.

f.  Unless otherwise specified on the engineering drawing or WPS, welded
    hardware will be delivered in the "as welded" condition. If
    required, any heat treatment processing required shall be detailed
    on the engineering drawing and shall include notation that will
    reference NASA/JSC PRC-2001 or PRC-2003 as applicable.

g.  Intermittent welding (skip welds) shall not be specified for Class A
    welds.

h.  Intermittent welds shall not be specified for groove welds (square
    or prepared groove design) unless the unwelded portions of the joint
    are adequately supported to prevent one member from coming out of
    plane with the adjoining member.

# **4.0 REFERENCES**

The standards and documents listed below shall be considered a part of
this specification to the extent specified herein. Unless otherwise
indicated, the revision that is in effect on the date of invitation for
bids or the date of request for proposals shall apply.

**a. American Society of Nondestructive Testing (ASNT)**

SNT-TC-1A *Personnel Qualification and Certification in Nondestructive
Testing*

**b. American Welding Society (AWS) Standards**

ANSI/AWS A2.4 *Standard Symbols for Welding, Brazing and Nondestructive
Testing*

ANSI/AWS A3.0 *Standard Welding Terms and Definitions*

ANSI/AWS A5.9 *Specification for Bare Stainless Steel Welding Electrodes
and Rods*

ANSI/AWS A5.12 *Specification for Tungsten Arc Welding Electrodes*

ANSI/AWS A5.14 *Specification for Nickel and Nickel Alloy Bare Welding
Electrodes and Rods*

ANSI/AWS A5.18 *Specification for Carbon Steel Filler Metals for Gas
Shielded Arc Welding*

ANSI/AWS A5.28 *Specification for Low Alloy Steel Filler Metals for Gas
Shielded Arc Welding*

ANSI/AWS B2.1 *Standard for Welding Procedure and Performance
Qualification*

ANSIAWS QC-1 *Standard for AWS Certification of Welding Inspectors*

**c. Compressed Gas Association, Inc.**

G-11.1 *Argon, Commodity Specification for*

**d. Military Documents**

MIL-A-18455 *Argon, Technical*

MIL-P-27407 *Propellant Pressurizing Agent, Helium*

MIL-P-27201 *Military Specification,* *Propellant, Hydrogen*

# **e. NASA/JSC Documents**

JPG 5322.1 *Contamination Control Requirements Manual*

PRC-2001 *Process Specification for the Heat Treatment of Steel Alloys*

PRC-2003 *Process Specification for the Heat Treatment of Nickel Alloys*

PRC-6503 *Process Specification for Radiographic Inspection*

PRC-6504 *Process Specification for the Ultrasonic Inspection of Wrought
Metals*

PRC-6505 *Process Specification for Magnetic Particle Inspection*

PRC-6506 *Process Specification for Liquid Penetrant Inspection*

SOP-004.5 *Control of Weld Filler Materials, Electrodes, and Fluxing
Materials*

SOP-007.1 *Preparation and Revision of Process Specifications*

TI-0000-04 *Training For Welders and Welding Operators*

**f. SAE / AMS Documents**

AMS-STD-1595 *Qualification of Aircraft, Missile and Aerospace Fusion
Welders*

## **5.0 [MATERIAL REQUIREMENTS]{.underline}**

All materials (base and filler materials as applicable) used in the
welding of hardware per this specification, shall meet the requirements
of an applicable JSC material specification unless otherwise specified.
If a JSC material specification is not available, then an applicable
commercial specification or a manufacturer\'s specification shall be
used.

### 

### **5.1 SHIELDING GASES**

Allowable shielding gases (including purge gases) are listed in Table I.
Gases purchased to alternate specifications shall be allowed provided
they meet the minimum requirements of the specifications listed herein.
Mixtures of these gases are allowed and the nominal mixture used for the
qualification welding shall be that used for production and shall be
listed on the WPS. Shielding and purging gas mixtures shall be subject
to the qualification variable requirements listed in AWS B2.1. In
addition:

a.  Hydrogen gas in any concentration, may not be used for welding any
    alloys known to be susceptible to hydrogen related problems (e.g.,
    alloy steels, Q&T steels, martensitic stainless steels, etc.).

b.  Nitrogen shall not be used for shielding or purging in any welding
    operation governed under this specification.

c.  All gases used for shielding or purging shall have a dewpoint of
    -40°F (minus 40 °C) or better.

### **5.2 FILLER METALS AND ELECTRODES**

All filler metals shall meet the requirements of the applicable AWS
filler metal specification relative to the specific alloy and process
being used. Filler metals shall be selected from Tables II, III, and IV.
If designated in **BOLD TYPE**, this shall be the first choice for
filler metal. Otherwise, selection shall be based on specific base metal
combinations, service environment, etc.). Tubular sleeve and filler
insert materials shall have compositions similar to those indicated in
Tables II, III, and IV. In addition, the following shall apply:

a)  For dissimilar metal welds joining carbon steel to low alloy steel,
    or between two different low alloy steels, filler metal with
    strength levels matching the lower strength material shall be used.
    For dissimilar metal joints involving stainless and corrosion
    resistant steels, nickel alloys, and/or other materials, filler
    metal selection shall be based on that stated herein and approved by
    the NASA/JSC M&P organization prior to use.

b)  All filler metals shall be used in accordance with a qualified WPS.

c)  Filler metal configurations which can not be procured to an AWS or
    other applicable filler metal specification shall meet an applicable
    NASA/JSC or other industry material specification and shall be
    approved by the NASA/JSC M&P organization prior to use.

d)  Non consumable tungsten and tungsten alloy electrodes for GTAW and
    PAW shall conform to the applicable AWS specification.

e)  Filler metals shall be listed on the engineering drawing.

**Table I. Allowable Shielding Gases**

  ------------------- --------------------------- -----------------------
  **Gas**             **Description**             **Specification**

  Argon               Gas                         MIL-A-18455

  Argon               Type II, Grade B            CGA G-11.1
                      (Liquefied)                 

  Carbon Dioxide      Grade B                     BB-C-101

  Helium              Type I, Grade A             MIL-P-27407

  Hydrogen            Gas                         MIL-P-27201

  Oxygen              Type I                      BB-O-925
  ------------------- --------------------------- -----------------------

**Table II. Approved Filler Metals for Welding Carbon and Low Alloy
Steel**

+----------+--------------------+--------------------+---------------+
| **MA     | **SMAW**           | **GTAW / GMAW**    | **FCAW**      |
| TERIAL** |                    |                    |               |
|          |                    | **and PAW**        |               |
| *        |                    |                    |               |
| *GROUP** |                    |                    |               |
+----------+--------------------+--------------------+---------------+
| **M-1**  | A5.1: E60XX,       | A5.28: E70S-2,     | A5.22:        |
|          | **E70XX** or       | E70S-3, **E70S-6** | **E70T-1**,   |
|          |                    |                    | E70T-5        |
|          | A5.5: E70XX-A1     |                    |               |
|          | ^(a)^              |                    |               |
+----------+--------------------+--------------------+---------------+
| **M-3**  | A5.5:              | A5.28:             | \(b\)         |
|          |                    |                    |               |
|          | E70XX-A1           | **ER80S** /        |               |
|          |                    | E80C-D2            |               |
+----------+--------------------+--------------------+---------------+
| **M-4**  | A-5.5:             | A5.28:             | \(b\)         |
|          |                    | **ER80S**,E80C-B2, |               |
|          | E80XX-B2           |                    |               |
|          |                    | ER80S / E80C-B2L   |               |
+----------+--------------------+--------------------+---------------+
| **M-5**  | A5.5:              | A5.28: **ER90S**,  | \(b\)         |
|          |                    | E80C-B3,           |               |
| **(3% Cr | E90XX-B3           |                    |               |
| max)**   |                    | ER90S / E90C-B3L   |               |
+----------+--------------------+--------------------+---------------+

> Notes:

(a) A5.5, E70XX-A1 shall be used for materials with maximum specified
    > carbon greater than 0.30%.

(b) Filler metal to be used for joining must be compositionally
    > compatible with base metal. Primary consideration shall be given
    > to mechanical properties, corrosion resistance, and weldability,
    > as applicable for the specific application.

(c) 

> **Table III. Approved Filler Metals for Welding Nickel Alloys**

+-------------------+-------------------------+-----------------------+
| **BASE METAL**    | **SMAW**                | **GTAW / GMAW / PAW** |
|                   |                         |                       |
|                   | **(AWS A5.11)**         | **(AWS A5.14)**       |
+-------------------+-------------------------+-----------------------+
| **Nickel 200**    | ENi-1                   | ERNi-1                |
|                   |                         |                       |
| **Nickel 201**    |                         |                       |
+-------------------+-------------------------+-----------------------+
| **Monel 400**     | ENiCu-7                 | ERNiCu-7              |
+-------------------+-------------------------+-----------------------+
| **Monel K500**    | \--                     | ERNiCu-7              |
+-------------------+-------------------------+-----------------------+
| **Inconel 600**   | **ENiCrFe-1**,          | **ERNiCrFe-5**,       |
|                   | ENiCrFe-3               | ERNiCr-3              |
+-------------------+-------------------------+-----------------------+
| **Inconel 601**   | **ENiCrFe-3**,          | **ERNiCr-3**,         |
|                   | ENiCrMo-3               | ERNiCrMo-3            |
+-------------------+-------------------------+-----------------------+
| **Inconel 625**   | ENiCrMo-3               | ERNiCrMo-3            |
+-------------------+-------------------------+-----------------------+
| **Inconel 718**   | \--                     | ERNiFeCr-2            |
|                   |                         |                       |
| **Inconel X750**  |                         |                       |
+-------------------+-------------------------+-----------------------+
| **Incoloy 800**   | **ENiCrFe-2**,          | **ERNiCr-3,**         |
|                   | ENiCrCoMo-1             | ERNiCrCoMo-1          |
+-------------------+-------------------------+-----------------------+
| **Incoloy 800HT** | ENiCrFe-2               | ERNiCr-3              |
+-------------------+-------------------------+-----------------------+
| **Incoloy 825**   | \--                     | ERNiFeCr-1            |
+-------------------+-------------------------+-----------------------+

**Table IV. Approved Filler Metals for Welding Austenitic Stainless
Steel**

+---------+------+------+--------+--------+--------+---------+-------+
| **AWS   | **3  | **30 | *      | *      | *      | *       | **    |
| M-8**   | 04** | 4L** | *309** | *310** | *316** | *316L** | 321** |
|         |      |      |        |        |        |         |       |
| **Base  | **3  |      |        |        |        |         | **    |
| M       | 08** |      |        |        |        |         | 347** |
| etal:** |      |      |        |        |        |         |       |
|         |      |      |        |        |        |         | **    |
|         |      |      |        |        |        |         | 348** |
+---------+------+------+--------+--------+--------+---------+-------+
| **301** | 308  | 308  | 308    | 308    | 308    | 308     | 308   |
|         |      |      |        |        |        |         |       |
| **302** | **30 | **30 | 308L   | 308L   | 308L   | 308L    | **3   |
|         | 8L** | 8L** |        |        |        |         | 08L** |
| **304** |      |      | 309    | 309    | 316    | 316     |       |
|         |      |      |        |        |        |         |       |
| **308** |      |      | **     | **     | **     | *       |       |
|         |      |      | 309L** | 309L** | 316L** | *316L** |       |
|         |      |      |        |        |        |         |       |
|         |      |      |        | 310    |        |         |       |
+---------+------+------+--------+--------+--------+---------+-------+
| *       | 308  | **30 | 308    | 308    | 308    | 308L    | **3   |
| *304L** |      | 8L** |        |        |        |         | 08L** |
|         | **30 |      | 308L   | 308L   | 308L   | *       |       |
|         | 8L** |      |        |        |        | *316L** | 347   |
|         |      |      | 309    | 309    | 316    |         |       |
|         |      |      |        |        |        | 309L    |       |
|         |      |      | **     | **     | **     |         |       |
|         |      |      | 309L** | 309L** | 316L** |         |       |
|         |      |      |        |        |        |         |       |
|         |      |      |        | 310    |        |         |       |
+---------+------+------+--------+--------+--------+---------+-------+
| **309** |      |      | 309    | 309    | 309    | 309     | 309   |
|         |      |      |        |        |        |         |       |
|         |      |      | **     | **     | 309L   | 309L    | **3   |
|         |      |      | 309L** | 309L** |        |         | 09L** |
|         |      |      |        |        | 316    | 316     |       |
|         |      |      |        | 310    |        |         | 347   |
|         |      |      |        |        | **     | *       |       |
|         |      |      |        |        | 316L** | *316L** |       |
+---------+------+------+--------+--------+--------+---------+-------+
| **310** |      |      |        | 310    | 316    | 316     | 308   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        | **     | *       | 308L  |
|         |      |      |        |        | 316L** | *316L** |       |
|         |      |      |        |        |        |         | **    |
|         |      |      |        |        | 310    | 310     | 310** |
+---------+------+------+--------+--------+--------+---------+-------+
| **316** |      |      |        |        | 316    | 316     | 308   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        | **     | *       | 308L  |
|         |      |      |        |        | 316L** | *316L** |       |
|         |      |      |        |        |        |         | 316   |
|         |      |      |        |        |        |         |       |
|         |      |      |        |        |        |         | **3   |
|         |      |      |        |        |        |         | 16L** |
+---------+------+------+--------+--------+--------+---------+-------+
| *       |      |      |        |        |        | 309L    | 309L  |
| *316L** |      |      |        |        |        |         |       |
|         |      |      |        |        |        | *       | **3   |
|         |      |      |        |        |        | *316L** | 16L** |
+---------+------+------+--------+--------+--------+---------+-------+
| **321** |      |      |        |        |        |         | 309L  |
|         |      |      |        |        |        |         |       |
| **347** |      |      |        |        |        |         | 321   |
|         |      |      |        |        |        |         |       |
| **348** |      |      |        |        |        |         | **    |
|         |      |      |        |        |        |         | 347** |
+---------+------+------+--------+--------+--------+---------+-------+

**5.2.1 [Control and Storage]{.underline}**

Welding electrodes shall be stored in a clean, dry, and controlled area
that provides protection from contamination, physical damage, and
commingling of alloys. Any form of electrodes or weld filler metal which
is damaged, dirty, exhibits oxidation/corrosion or has been contaminated
with water, oil, grease or any form of hydrocarbons shall not be used
and shall be disposed of in accordance with an appropriate disposal
procedure. For JSC operations, welding electrodes and filler materials
shall be controlled in accordance with SOP-004.5. Outside vendors shall
provide control and storage according to the applicable material
specification or manufacturer\'s recommendation, whichever is more
rigid.

# **6.0 PROCESS REQUIREMENTS**

All weldments shall be fabricated according to the requirements of this
process specification. The requirements of the applicable codes and
standards listed in Section 4.0, shall be met as specified by this PRC
based on the design and intended function of the hardware. Certain
paragraphs of this process specification are abbreviated re-statements
taken from the applicable standards and are included here for the user's
convenience. The remaining paragraphs of this process specification
represent requirements imposed in addition to the basic requirements of
the applicable codes and standards.

All arc welding shall be performed using Welding Procedure
Specifications (WPS) that have been qualified in accordance with the
requirements of Section 6.2. To accommodate any unique differences due
to tooling, fixtures, grounding, etc. in the weld parameter settings
between a test specimen welding condition and a production component
welding condition, a one time adjustment to the heat input specific
parameters shall be allowed with no additional qualification testing
required. This adjustment in setting(s) shall be allowed on the "first
production component" only. The specific changes shall be documented on
a revised WPS reflecting the statement "First Production Component
Adjustment" to differentiate from the original WPS.

1.  **Welding Precision Cleaned Hardware (including tube preparation for
    welding)**

Whenever precision-cleaned hardware must be maintained clean during
welding into an assembly, the welding operation shall be performed in a
dedicated Class 100,000 Clean Work Area. This may require temporary
tents over the weld area and/or local monitors located in the area of
welding to ensure the Class 100,000 environment is being met. Portable
particle counters shall be located as close as possible to the work
area, so as to monitor local contaminants during tube preparation and
welding. Tools used in weld preparation and welding (such as cutter,
weld head, files) shall be visibly cleaned per JPG 5322.1 and maintained
clean (e.g. bagged when not in use).

For hardware that cannot be subsequently precision-cleaned, a proven
method for protecting against system contamination during tube
preparation and welding shall be implemented. One such method is the use
of a physical barrier, such as plugs. The installation and removal of
plugs shall be tracked by a reliable method and independently verified.
Prior to plug removal, the exposed internal surfaces of the tube shall
be cleaned using a swab wetted with an approved solvent, and positive
backpressure shall be maintained as the plug is removed.

Tube cutters shall use a sharp blade, changed frequently. Cutting shall
be performed with minimal cutter pressure to aid in preventing particle
generation. Vacuum shall be used during tube facing operations to remove
particulate. Whenever possible, facing operations shall be performed
away from the weld assembly area, to reduce particulate contamination of
the welding work area. Tube facing shall be performed without the use of
cutting oils, other fluids, lubricants or coolants. Abrasives, including
sandpaper or abrasive pads, shall not be used inside tubes or when
unprotected internal surfaces are exposed. After each tube preparation,
and prior to welding, a high-velocity gas purge shall be performed. The
purge gas velocity shall be the maximum attainable using a 90-psig
source. The purge gas used during facing and welding shall meet the
hydrocarbon and particulate requirements for the system under assembly.
The purge gas shall be supplied in accordance with Section 5.1.

## **6.2 PROCESS-SPECIFIC REQUIREMENTS**

### 

### **6.2.1 Gas Tungsten Arc Welding**

Additional filler metal shall be used with the GTAW process unless it
can be demonstrated by weld qualification that weld cracking and other
undesirable metallurgical conditions will not exist in the finished weld
made without filler metal (autogenous weld). This method of welding
shall be specified on an approved WPS.

### **6.2.2 Plasma Arc Welding**

Additional filler metal shall be used with the PAW process unless it can
be demonstrated by weld qualification that weld cracking and other
undesirable metallurgical conditions will not exist in the finished weld
made without filler metal (autogenous weld). This method of welding
shall be specified on an approved WPS.

## **6.3 Weld Qualification**

This specification provides specific allowances for components that are
fabricated for pressure containing applications and non pressure
containing (i.e., structural only) applications.

**6.3.1 [Pressure Containing Components]{.underline}**

A Welding Procedure Specification (WPS) shall be qualified for each
unique weld type (as detailed in 6.2.1.1) to be produced, before the
production welds are made. An existing qualified WPS for one unique weld
type may be used for a different engineering drawing provided the
requirements of 6.2.1.1 are met, and it is demonstrated that the
essential weld variables listed in Table V will be met. Demonstration
shall constitute all the requirements of Section 6.2.3 except that no
additional documentation is required except, when a WPS(s) is written
for a specific item(s) of hardware, it shall be revised/amended to show
allowance for use on other than the initial specifically stated
hardware. The actual welding variables, methods, practices, specific
tooling requirements, and test results used during WPS qualification
shall be recorded on a Procedure Qualification Record (PQR).

**6.3.1.1 Unique Weld Type**

A "Unique Weld Type" includes those weld joint configurations that
differ from one another in any of the following respects:

1.  Base material thickness,

2.  Base material type (M-number/alloy),

3.  Square groove joint vs. bevel, V, or U-groove joints,

4.  Groove joint vs. fillet weld,

5.  Addition or deletion of filler material,

6.  Addition, deletion, or change in the Preheat, Interpass, or Post
    Weld Heat Treat (PWHT) requirements.

**6.3.1.2 Test Requirements**

At a minimum, the following are minimum requirements for the
qualification of a welding procedure. This effort shall include the
welding of a minimum of 9 weld samples that represent the weld type
specified. Three of these welds shall be made at a "nominal" heat input
setting, 3 shall be made at a "limit low" heat input setting, and 3
shall be made at a "limit high" heat input setting. All samples shall be
visually inspected on the O.D. and I.D. to Class A criteria and
radiographically inspected to Class A criteria. If the weld procedure
includes a PWHT, the radiographic inspection shall, at a minimum, be
performed after the PWHT cycle. Two samples from each group shall be
mechanically tested in tension and the results evaluated to the
requirements of AWS B2.1. One sample from each group shall be sectioned
and metallographically examined and the results evaluated to the
requirements of AWS B2.1. Photomicrographs shall be taken of the
prepared samples and retained with the PQR.

**6.3.1.3 Essential Variables**

The WPS shall specify all of the essential welding variables and the
applicable allowable ranges qualified for each variable, as indicated in
Table V. In addition, the WPS shall detail all methods, practices,
specific tooling requirements that are determined necessary by the
operating facility to successfully execute the weld in production.

Table V - Essential Welding Variables

+----------+----------------------------------------------+------------+
| Variable | Variable / Weld Type                         | Range      |
| \#       |                                              |            |
|          |                                              | Allowed    |
+----------+----------------------------------------------+------------+
| 1        | Power Source Model \#                        | None       |
+----------+----------------------------------------------+------------+
| 2        | Weld Head Model \#                           | None       |
+----------+----------------------------------------------+------------+
| 3        | Joint Configuration                          | None       |
+----------+----------------------------------------------+------------+
| 4        | Groove Angle                                 | +/- 5^o^   |
+----------+----------------------------------------------+------------+
| 5        | Nominal Tube Dia.                            | None       |
+----------+----------------------------------------------+------------+
| 6        | Nominal Wall Thickness                       | None       |
+----------+----------------------------------------------+------------+
| 7        | Material Type(s)                             | None       |
+----------+----------------------------------------------+------------+
| 8        | Electrode Start Position                     | +/- 60^o^  |
+----------+----------------------------------------------+------------+
| 9        | Preweld Cleaning Steps                       | None       |
+----------+----------------------------------------------+------------+
| 10       | Allowable Joint Gap                          | None       |
+----------+----------------------------------------------+------------+
| 11       | Tool or Shop Aid Identification              | None       |
+----------+----------------------------------------------+------------+
| 12       | Preweld Purge Time                           | \(1\)      |
+----------+----------------------------------------------+------------+
| 13       | Postweld Purge Time                          | \(1\)      |
+----------+----------------------------------------------+------------+
| 14       | Tube ID Prepurge Flow Rate or Pressure       | None       |
+----------+----------------------------------------------+------------+
| 15       | Weld Head Prepurge Flow Rate                 | +/- 15%    |
+----------+----------------------------------------------+------------+
| 16       | Plasma Gas Flow Rate                         | +/- 10%    |
+----------+----------------------------------------------+------------+
| 17       | Gas Composition/Spec.                        | None       |
+----------+----------------------------------------------+------------+
| 18       | Electrode Travel Speed & Machine Setting     | None       |
+----------+----------------------------------------------+------------+
| 19       | Arc Travel Start Delay                       | None       |
+----------+----------------------------------------------+------------+
| 20       | Total Weld Current On Time                   | None       |
+----------+----------------------------------------------+------------+
| 21       | Weld Time @ Level or Circumference Interval  | None       |
+----------+----------------------------------------------+------------+
| 22       | Current Pulse Width (%)                      | None       |
+----------+----------------------------------------------+------------+
| 23       | Current Pulse Rate                           | None       |
+----------+----------------------------------------------+------------+
| 24       | Filler Material / Spec.                      | None       |
+----------+----------------------------------------------+------------+
| Variable | Variable / Weld Type                         | Range      |
| \#       |                                              |            |
|          |                                              | Allowed    |
+----------+----------------------------------------------+------------+
| 25       | Filler Wire Feed Speed                       | +/- 50%    |
+----------+----------------------------------------------+------------+
| 26       | Consumable Insert Type and Specification     | None       |
+----------+----------------------------------------------+------------+
| 27       | Tubular Sleeve Spec.                         | None       |
+----------+----------------------------------------------+------------+
| 28       | Background Welding Current                   | None       |
+----------+----------------------------------------------+------------+
| 29       | Pulse Welding Current                        | None       |
+----------+----------------------------------------------+------------+
| 30       | Electrode Type                               | None       |
+----------+----------------------------------------------+------------+
| 31       | Electrode Diameter                           | None       |
+----------+----------------------------------------------+------------+
| 32       | Electrode Tip Geometry                       | None       |
+----------+----------------------------------------------+------------+
| 33       | GTAW Electrode to Work Gap (nom. setting)    | +/- 10%    |
+----------+----------------------------------------------+------------+
| 34       | PAW Electrode Position Setting (nom.         | +/- 10%    |
|          | setting)                                     |            |
+----------+----------------------------------------------+------------+
| 35       | PAW Orifice Size                             | None       |
+----------+----------------------------------------------+------------+
| 36       | Minimum Preheat Temp.                        | None       |
+----------+----------------------------------------------+------------+
| 37       | Maximum Interpass Temp.                      | None       |
+----------+----------------------------------------------+------------+
| 38       | PWHT Procedure/Spec.                         | None       |
+----------+----------------------------------------------+------------+

**6.3.2 [Non Pressure Containing Piping and Tubing Components and
Structural Components]{.underline}**

A Welding Procedure Specification (WPS) shall be qualified for each
unique weld type (as detailed in 6.2.2.1) to be produced by conforming
to the requirements below, before the production welds are made. An
existing qualified WPS for one unique weld type may be used for a
different engineering drawing provided the requirements of 6.2.2.1 are
met, and it is demonstrated that the procedure qualification variables
(essential variables) listed in AWS B2.1 will be met. Demonstration
shall constitute all the requirements of Section 6.2.3 except that no
additional documentation is required except, when a WPS(s) is written
for a specific item(s) of hardware, it shall be revised/amended to show
allowance for use on other than the initial specifically stated
hardware. The actual welding variables, methods, practices, specific
tooling requirements, and test results used during WPS qualification
shall be recorded on a Procedure Qualification Record (PQR).

**6.3.2.1 Unique Weld Type**

A "Unique Weld Type" includes those weld joint configurations that
differ from one another in any of the following respects:

1.  Base material thickness,

2.  Base material type (M-number/alloy),

3.  Square groove joint vs. bevel, V, or U-groove joints,

4.  Groove joint vs. fillet weld,

5.  Addition or deletion of filler material,

6.  Addition, deletion, or change in the Preheat, Interpass, or Post
    Weld Heat Treat (PWHT) requirements,

7.  Addition or deletion of backing.

**6.3.2.2 Test Requirements**

At a minimum, the welding and testing requirements for non pressure
containing tubing and piping applications, or structural applications
shall conform to the requirements of AWS B2.1.

**6.3.2.3 Essential Variables**

The WPS shall specify all of the essential welding variables as
indicated in AWS B2.1 and the applicable allowable ranges qualified for
each variable, as specified in AWS B2.1. In addition, the WPS shall
detail all methods, practices, specific tooling requirements that are
determined necessary by the operating facility to successfully execute
the weld in production.

**6.3.3 Requalification of WPS**

Requalification of the WPS shall be required when any of the following
conditions exist:

a)  The weld system has been placed on a different external power source
    except when the power supply has a means for internal power
    regulation,

b)  Major maintenance has been performed on the weld system. Major
    maintenance includes replacement of the power supply, major repair
    of the power supply requiring entrance into the controller welding
    power supply, or replacement of the weld head has occurred,

c)  Preproduction weld samples do not meet requirements and no
    assignable cause for the failure can be determined.

Requalification may be performed with less total test sample
requirements than that required for an initial qualification for a
unique weld type. For requalification, only 2 weld samples shall be
produced and submitted; one at the "high limit" setting and one at the
"low limit" setting for that WPS. Requalification due to item a) or b)
above only requires weld samples to be made from one WPS that is
specified for use on that system.

The samples shall, at a minimum, be subjected to visual inspection and
volumetric NDE and shall meet the applicable requirements specified
herein. Requalification results shall be documented on a PQR with a
specific notation made indicating "Requalification" and an explanation
as to the cause. If the requalification activities result in any welding
parameter(s) deviations that exceed the range specified in Table V or
AWS B2.1 as applicable, for that parameter, then the level of testing in
6.2.4 shall be required.

## **6.4 PREHEATING**

Preheat shall not exceed the temperature specified in the applicable
WPS. In weld joints between different base metal types and thickness,
the higher of the preheat requirements of the joint members shall apply.

## **6.5 INTERPASS TEMPERATURE**

a\. In weld joints between different base metal types and thickness, the
higher of the preheat requirements of the joint members shall apply.

b\. Minimum interpass temperature during welding shall be the same as
the minimum preheat temperature specified in the welding procedure
specification and shall be maintained by the application of concurrent
heat if necessary.

c\. The maximum interpass temperature for welding quenched and tempered
steels shall be at least 50^o^ F below the nominal tempering temperature
and is limited to this temperature in order to ensure adherence to the
steel manufacturer's recommendations regarding heat input.

## 

## **6.6 POST WELD HEAT TREATMENT (PWHT)**

Postweld heat treatment, when required by the engineering drawing or
WPS, shall be performed after completion of all welding in accordance
with NASA/JSC PRC-2001 or PRC-2003, as applicable. Vibratory techniques
shall not be used in place of thermal treatments.

## **6.7 WELD REPAIRS AND WELDED REPAIRS TO BASE METAL**

All weld and welded repairs shall be performed using the WPS used for
the original weld or a specific qualified WPS for that repair and shall
meet all of the requirements of the original drawing and any additional
requirements that are documented in the WPS. A weld repair may be
applied manually in lieu of an automated or machine applied repair,
provided the essential variables/parameters of the original WPS are
duplicated and the heat input applied is less than the initial weld.
Weld repair does not include the correction of dimensional or other
deficiencies of weld joints groove/bevel preparation by "buttering" or
build up provided the area corrected by welding is fully consumed in the
final weld. Also, the following requirements shall be required in the
weld repair activity:

a)  [Defect Removal]{.underline}. Defect removal shall be by means of
    grinding, chipping, or machining, or a combination of these methods.
    Thermal gouging and cutting may be used on carbon and low alloy
    steels provided the excavated cavity is finished by grinding to
    sound metal. The final repair cavity shall be of a configuration
    suitable for welding. The excavation shall be subjected to visual
    and/or NDE inspections to ensure defect removal prior to welding.
    Weld repairs shall be adequately documented by the use of a weldment
    map or other manufacturing record with sufficient detail to ensure
    identification of the weldment, identification of repair
    location(s), and type of defect.

b)  [Repair]{.underline}. No more than two weld attempts shall be made
    to successfully complete a welded repair. If a second attempt is
    unsuccessful, a discrepancy report shall be generated and shall
    require dispositioning by the responsible Material Review Board
    (MRB). The level of documentation of repair welds shall, at a
    minimum, be consistent with that required for the original
    production weld.

c)  [Straightening]{.underline}. Welds or adjacent base metal which have
    been deformed by the welding operation may be straightened. All
    straightening operations shall take place at temperatures not to
    exceed 121°C (250°F). All straightening operations must be validated
    by an appropriate method(s) to show that the process used for
    straightening shall not degrade the joint or surrounding material
    below specified design requirements.

d)  [Base Metal Repairs.]{.underline} Repairs to base metal anomalies
    shall be brought to the attention of the NASA/JSC M&P organization
    for consideration of cause, prior to repair activities.

**7.0 PROCESS VERIFICATION**

Process verification shall consist of visual inspection and/or
nondestructive inspection, as described further in sections 7.1 to 7.3.
In addition, at the appropriate time during the fabrication activities,
the following items shall be verified:

a)  Verify that the welder is certified for the specific welding
    operation (prior to welding).

b)  Fit-up in accordance with the engineering drawing (prior to welding
    for Class A Pressure Containing Components).

c)  A WPS exists (prior to welding).

d)  Compliance with WPS for essential variable ranges (during welding).

e)  PWHT in accordance with the assigned WPS (after welding).

## 

## **7.1 INSPECTION**

### **7.1.1 Class A Inspection - Pressure Containing Components**

a)  Unless otherwise specified, Class A joints require visual inspection
    and volumetric inspection using either the radiographic method or
    ultrasonic method to the Class A acceptance criterias in Appendix A.

b)  In cases where the Class A inspection is designated for a fillet
    joint, or for any joint having a configuration which renders
    radiography or ultrasonics an impractical method, an alternate
    inspection method shall be utilized with approval from the
    responsible NASA/JSC M&P organization.

c)  When the liquid penetrant or magnetic particle method is selected as
    an alternate to volumetric inspection for multipass welds,
    inspections shall be performed on the root pass, each ¼" thick layer
    of weld metal, and the final or cover pass.

### 

### **7.1.1.1 Class A Inspection - Non Pressure Containing Piping and Tubing Components and Structural Components**

a)  Unless otherwise specified, Class A joints require visual inspection
    and volumetric inspection using either the radiographic method or
    ultrasonic method to the Class A acceptance criterias in Appendix B.

b)  In cases where the Class A inspection is designated for a fillet
    joint, or for any joint having a configuration which renders
    radiography or ultrasonics an impractical method, an alternate
    inspection method shall be utilized with approval from the
    responsible NASA/JSC M&P organization.

c)  When the liquid penetrant or magnetic particle method is selected as
    an alternate to volumetric inspection for multipass welds,
    inspections shall be performed on the root pass, each ¼" thick layer
    of weld metal, and the final or cover pass.

**7.1.2 [Class B Inspection - Pressure Containing
Components]{.underline}**

Unless otherwise specified in design documentation, Class B joints
require visual inspection and liquid penetrant or magnetic particle
inspection to the Class B acceptance criterias in Appendix A.

**7.1.2.1 [Class B Inspection - Non Pressure Containing Piping and
Tubing Components and Structural Components]{.underline}**

Unless otherwise specified in design documentation, Class B joints
require visual inspection and liquid penetrant or magnetic particle
inspection to the Class B acceptance criterias in Appendix B.

**7.1.3 [Class C Inspection - Non Pressure Containing Piping and Tubing
Components and Structural Components]{.underline}**

###  

Unless otherwise specified in design documentation, Class C joints
require visual inspection to the Class C acceptance criteria in Appendix
B.

## **7.2 VISUAL INSPECTION REQUIREMENTS**

All visual inspections of welded joints shall be performed by an
American Welding Society (AWS) Certified Welding Inspector (CWI)
qualified in accordance with AWS QC-1. The CWI certification must be
current.

## **7.3 NON-DESTRUCTIVE EVALUATION (NDE)**

The NDE of welded joints shall be performed by personnel qualified in
accordance with the requirements of the applicable NDE process
specification. The NDE certification must be current. All nondestructive
inspections shall be performed in accordance with the appropriate
standards as referenced herein.

# **8.0 PROCESS DOCUMENTATION REQUIREMENTS**

The WPS, PQR, and WOPQ shall be prepared and retained as a permanent
record and made available upon request to the NASA/JSC M&P organization
for review**.** These procedures must contain, at a minimum, all of the
essential welding parameters, an identification of the welding
equipment, and include any pertinent tooling information. One copy of
the WPS shall be maintained in the vicinity of the welding station and
shall be readily accessible by the welders, inspectors, supervision, and
engineering.

## 

**8.1 WELDING PROCEDURE SPECIFICATION**

A Welding Procedure Specification (WPS) is a qualified written working
procedure that must be developed before beginning production for each
unique weld type to be produced. Qualification support documentation in
the form of a Procedure Qualification Record (PQR) shall be maintained
on file to show proof of process/procedure capability using the WPS. The
WPS shall be traceable by means of serialized nomenclature and shall
show traceability to the applicable PQR(s). The WPS used for production
welding shall meet the requirements stated herein and shall be certified
by the responsible M&P organization at the operating facility, prior to
use in production. "Prequalified" or "Standard Welding Procedure
Specifications" shall not be permitted for production use on Class A or
B welds made on flight hardware.

**8.2 PROCEDURE QUALIFICATION RECORD**

A Procedure Qualification Record (PQR) is documentation to support the
welding procedure specification to show proof of process/procedure
capability. A PQR shall be unique and traceable, by means of serialized
nomenclature. The PQR shall be process-specific and specific to a unique
weld type. Data required in the PQR shall include detailed descriptions
of the test coupon configurations and joint designs, all pertinent
material specifications, all pertinent essential process variables used,
all destructive and nondestructive test results from the qualification
sample set, and all required certifications from the approving
organization. The PQR shall be approved by the responsible M&P
organization at the operating facility.

## **8.3 WELDING OPERATOR PERFORMANCE QUALIFICATION**

A Welding Operator Performance Qualification (WOPQ) is documentation
that shows that a welding operator has been tested in accordance with
AMS-STD-1595 and shown competent to produce a sound weld for a specific
welding process/base material/base metal thickness combination.

## **8.4 DEVIATIONS AND WAIVERS**

Any deviations or waivers regarding the use of this process
specification shall be requested in writing by the outside vendor. This
request shall be directed to the NASA/JSC M&P organization with the
appropriate justification and rationale. A written response will be
provided upon such a request.

# **9.0 TRAINING AND CERTIFICATION OF PERSONNEL**

## **9.1 TRAINING**

At JSC, if welder training is considered necessary prior to
qualification/requalification of existing JSC welding personnel or the
initial qualification of new hires, it shall be conducted in accordance
with TI-0000-04. For an outside JSC vendor, welder training (when
necessary) should consist of practice using the facility welding
equipment and a specific WPS to demonstrate proficiency, under the
supervision of a qualified/certified welder. Specific development of an
appropriate training program shall be the responsibility of the vendor.

## 

## **9.2 WELDING OPERATOR QUALIFICATION**

Welding shall be performed by a welding operator qualified and certified
in accordance with AMS-STD-1595 with the exception that mandatory 5 year
requalification is not required provided the operator continuity
requirement discussed below is maintained. Sufficiently detailed records
shall be maintained to demonstrate continuity of operator performance on
the welding system or system(s) on a semi-annual (6 month) basis. These
records shall be made available to the NASA/JSC M&P organization upon
request.

**[APPENDIX A]{.underline}**

**[SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS A -]{.underline}**

**[Pressure Containing Components]{.underline}**

  --------------- -------------------------------------------------------
  Size and        Minimum size as specified on drawing. If profile
  Appearance of   requirements are not specified on the drawing, the weld
  Groove Welds    shall be convex with a maximum reinforcement as stated
                  herein. Any profile is unacceptable where the weld to
                  base metal transition forms a sharp notch or reduces
                  the base metal thickness (T) beyond the minimum
                  specified on the drawing.

  Size and        Minimum size as specified on drawing. If profile
  Appearance of   requirements are not specified on the drawing, the weld
  Fillet Welds    shall be flat or slightly convex with a maximum
                  reinforcement as stated herein. Any profile is
                  unacceptable where the weld to base metal transition
                  forms a sharp notch or reduces (T) beyond the minimum
                  specified on the drawing.

  Cracks          None allowed.

  Undercut        Undercut shall not exceed 20% of the total weld length.
                  The depth of any undercut indication where T \< 0.035",
                  undercut shall not exceed 5% of T. Where T is \>/=
                  0.035" and \</= 0.09", undercut shall not exceed 10% of
                  T or 0.010", whichever is the lesser. Where T \> 0.09",
                  the depth of undercut shall not exceed 0.010". The
                  minimum distance allowed between adjacent undercut or
                  underbead concavity indications is 1/2 the length of
                  the longest adjacent indication.

  Pores or Voids  The maximum diameter shall not exceed 0.02" or ¼ of T,
                  whichever is the lesser. Indications less than .010" in
                  diameter shall not be considered.

  Inadequate      The maximum length of any indication shall not exceed ¼
  Penetration and of T in any weld length of 6T or less. The minimum
  Incomplete      distance allowed between adjacent incomplete
  Fusion          penetration or fusion indications, is ½ the length of
                  the longest adjacent indication.

  Weld Face or    Concavity shall not exceed 10% of T or 0.01", whichever
  Root Concavity  is the lesser.
  or WM Thinning  

  Overlap         None allowed.

  Misalignment    Misalignment shall not exceed 10% of T, or 0.020",
                  whichever is the lesser.

  Peaking         Weld joint peaking shall not exceed a total of 5
                  degrees.

  Weld Face or    Reinforcement, or melt-thru, shall not exceed 20% T or
  Root Convexity  0.06", whichever is the lesser.

  Surface         A black - brown color is not allowed.
  Discoloration   

  Surface         Surface finish of welds and adjacent material resulting
  Roughness       from processes used to remove weld reinforcement and
                  otherwise shall not exceed 63 microinches.

  General         Weld deposits, face and root reinforcement and adjacent
  Workmanship     base metal shall display a smooth and uniform
                  appearance. The weld toes shall blend smoothly into the
                  base metal without unfused overlaps or undercut
                  exceeding that specified.
  --------------- -------------------------------------------------------

**[APPENDIX A]{.underline}**

**[SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS B -]{.underline}**

**[Pressure Containing Components]{.underline}**

  ---------------- ------------------------------------------------------
  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Groove Welds     weld shall be convex with a maximum reinforcement as
                   stated herein. Any profile is unacceptable where the
                   weld to base metal transition forms a sharp notch or
                   reduces the base metal thickness (T) beyond the
                   minimum specified on the drawing.

  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Fillet Welds     weld shall be flat or slightly convex with a maximum
                   reinforcement as stated herein. Any profile is
                   unacceptable where the weld to base metal transition
                   forms a sharp notch or reduces (T) beyond the minimum
                   specified on the drawing.

  Cracks           None allowed.

  Undercut         Undercut shall not exceed 15% of the total weld
                   length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 10% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 15% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.015".

  Pores or Voids   The maximum diameter shall not exceed 0.02" or 1/3 of
                   T, whichever is the lesser. Indications less than
                   .010" in diameter shall not be considered.

  Weld Face or     Concavity shall not exceed 15% of T or 0.015",
  Root Concavity   whichever is the lesser.
  or WM Thinning   

  Overlap          None allowed.

  Misalignment     Misalignment shall not exceed 15% of T or 0.025",
                   whichever is the lesser.

  Peaking          Weld joint peaking shall not exceed a total of 5
                   degrees.

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% T or
  Root Convexity   0.06", whichever is the lesser.

  Surface          A black - brown color is not allowed.
  Discoloration    

  Surface          Surface finish of welds and adjacent material
  Roughness        resulting from processes used to remove weld
                   reinforcement and otherwise shall not exceed 63
                   microinches.

  General          Weld deposits, face and root reinforcement and
  Workmanship      adjacent base metal shall display a smooth and uniform
                   appearance. The weld toes shall blend smoothly into
                   the base metal without unfused overlaps or undercut
                   exceeding that specified.
  ---------------- ------------------------------------------------------

**[APPENDIX A]{.underline}**

**[SUB SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS A -]{.underline}**

**[Pressure Containing Components]{.underline}**

  ---------------- ------------------------------------------------------
  Cracks           None allowed.

  Cold Shut and    None allowed.
  Laps             

  Porosity and     The maximum diameter shall not exceed 0.02" or ¼ of T,
  Inclusions       whichever is the lesser. Indications less than .010"
                   in diameter shall not be considered.

  Inadequate       The maximum length of any indication shall not exceed
  Penetration and  ¼ of the base metal thickness in any weld length of 6T
  Incomplete       or less. The minimum distance allowed between adjacent
  Fusion           incomplete penetration or fusion indications, is ½ the
                   length of the longest adjacent indication.

  Undercut and     The length of any undercut or underbead concavity
  Underbead        indication shall not exceed 20% of the total weld
  Concavity        length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 5% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 10% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.010". The minimum distance allowed between
                   adjacent undercut or underbead concavity indications
                   is 1/2 the length of the longest adjacent indication.

  Misalignment     Misalignment shall not exceed 10% of T, or 0.020",
                   whichever is the lesser.

  Weld Face or     Thinning shall not exceed 10% of T or 0.01", whichever
  Root Concavity   is the lesser.
  or WM Thinning   

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% of T
  Root Convexity   or 0.06", whichever is the lesser.
  ---------------- ------------------------------------------------------

**[APPENDIX A]{.underline}**

**[SUB SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS B -]{.underline}**

**[Pressure Containing Components]{.underline}**

  ---------------- ------------------------------------------------------
  Cracks           None allowed.

  Cold Shut and    None allowed.
  Laps             

  Porosity and     The maximum diameter shall not exceed 0.02" or 1/3 of
  Inclusions       T, whichever is the lesser. Indications less than
                   .010" in diameter shall not be considered.

  Inadequate       The maximum length of any indication shall not exceed
  Penetration and  1/3 of the T in any weld length of 6T or less. The
  Incomplete       minimum distance allowed between adjacent incomplete
  Fusion           penetration or fusion indications, is ½ the length of
                   the longest adjacent indication.

  Undercut and     The length of any undercut or underbead concavity
  Underbead        indication shall not exceed 15% of the total weld
  Concavity        length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 10% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 15% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.015". The minimum distance allowed between
                   adjacent undercut or underbead concavity indications
                   is 1/2 the length of the longest adjacent indication.

  Misalignment     Misalignment shall not exceed 15% of T, or 0.025",
                   whichever is the lesser.

  Weld Face or     Thinning shall not exceed 15% of T or 0.015",
  Root Concavity   whichever is the lesser.
  or WM Thinning   

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% of T
  Root Convexity   or 0.06", whichever is the lesser.
  ---------------- ------------------------------------------------------

**[APPENDIX B]{.underline}**

**[SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS A -]{.underline}**

**[Non Pressure Containing Piping and Tubing Components and Structural
Components]{.underline}**

  ---------------- ------------------------------------------------------
  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Groove Welds     weld shall be convex with a maximum reinforcement as
                   stated herein. Any profile is unacceptable where the
                   weld to base metal transition forms a sharp notch or
                   reduces the base metal thickness (T) beyond the
                   minimum specified on the drawing.

  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Fillet Welds     weld shall be flat or slightly convex with a maximum
                   reinforcement as stated herein. Any profile is
                   unacceptable where the weld to base metal transition
                   forms a sharp notch or reduces (T) beyond the minimum
                   specified on the drawing.

  Cracks           None allowed.

  Undercut         Undercut shall not exceed 15% of the total weld
                   length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 10% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 15% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.015".

  Pores or Voids   The maximum diameter shall not exceed 0.02" or 1/3 of
                   T, whichever is the lesser. Indications less than
                   .010" in diameter shall not be considered.

  Weld Face or     Concavity shall not exceed 15% of T or 0.015",
  Root Concavity   whichever is the lesser.
  or WM Thinning   

  Overlap          None allowed.

  Misalignment     Misalignment shall not exceed 15% of T or 0.025",
                   whichever is the lesser.

  Peaking          Weld joint peaking shall not exceed a total of 5
                   degrees.

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% T or
  Root Convexity   0.06", whichever is the lesser.

  Surface          A black - brown color is not allowed.
  Discoloration    

  Surface          Surface finish of welds and adjacent material
  Roughness        resulting from processes used to remove weld
                   reinforcement and otherwise shall not exceed 63
                   microinches.

  General          Weld deposits, face and root reinforcement and
  Workmanship      adjacent base metal shall display a smooth and uniform
                   appearance. The weld toes shall blend smoothly into
                   the base metal without unfused overlaps or undercut
                   exceeding that specified.
  ---------------- ------------------------------------------------------

**[APPENDIX B]{.underline}**

**[SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS B and C
-]{.underline}**

**[Non Pressure Containing Piping and Tubing Components and Structural
Components]{.underline}**

  ---------------- ------------------------------------------------------
  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Groove Welds     weld shall be convex with a maximum reinforcement as
                   stated herein. Any profile is unacceptable where the
                   weld to base metal transition forms a sharp notch or
                   reduces the base metal thickness (T) beyond the
                   minimum specified on the drawing.

  Size and         Minimum size as specified on drawing. If profile
  Appearance of    requirements are not specified on the drawing, the
  Fillet Welds     weld shall be flat or slightly convex with a maximum
                   reinforcement as stated herein. Any profile is
                   unacceptable where the weld to base metal transition
                   forms a sharp notch or reduces (T) beyond the minimum
                   specified on the drawing.

  Cracks           None allowed.

  Undercut         Undercut shall not exceed 15% of the total weld
                   length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 10% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 15% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.015".

  Pores or Voids   The maximum diameter shall not exceed 0.02" or 1/3 of
                   T, whichever is the lesser. Indications less than
                   .010" in diameter shall not be considered.

  Weld Face or     Concavity shall not exceed 15% of T or 0.015",
  Root Concavity   whichever is the lesser.
  or WM Thinning   

  Overlap          None allowed.

  Misalignment     Misalignment shall not exceed 15% of T or 0.025",
                   whichever is the lesser.

  Peaking          Weld joint peaking shall not exceed a total of 5
                   degrees.

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% T or
  Root Convexity   0.06", whichever is the lesser.

  Surface          A black - brown color is not allowed.
  Discoloration    

  Surface          Surface finish of welds and adjacent material
  Roughness        resulting from processes used to remove weld
                   reinforcement and otherwise shall not exceed 63
                   microinches.

  General          Weld deposits, face and root reinforcement and
  Workmanship      adjacent base metal shall display a smooth and uniform
                   appearance. The weld toes shall blend smoothly into
                   the base metal without unfused overlaps or undercut
                   exceeding that specified.
  ---------------- ------------------------------------------------------

**[APPENDIX B]{.underline}**

**[SUB SURFACE INSPECTION ACCEPTANCE CRITERIA - CLASS A and
B-]{.underline}**

**[Non Pressure Containing Piping and Tubing Components and Structural
Components]{.underline}**

  ---------------- ------------------------------------------------------
  Cracks           None allowed.

  Cold Shut and    None allowed.
  Laps             

  Porosity and     The maximum diameter shall not exceed 0.02" or 1/3 of
  Inclusions       T, whichever is the lesser. Indications less than
                   .010" in diameter shall not be considered.

  Inadequate       The maximum length of any indication shall not exceed
  Penetration and  1/3 of the T in any weld length of 6T or less. The
  Incomplete       minimum distance allowed between adjacent incomplete
  Fusion           penetration or fusion indications, is ½ the length of
                   the longest adjacent indication.

  Undercut and     The length of any undercut or underbead concavity
  Underbead        indication shall not exceed 15% of the total weld
  Concavity        length. The depth of any undercut indication where T
                   \< 0.035", undercut shall not exceed 10% of T. Where T
                   is \>/= 0.035" and \</= 0.09", undercut shall not
                   exceed 15% of T or 0.010", whichever is the lesser.
                   Where T \> 0.09", the depth of undercut shall not
                   exceed 0.015". The minimum distance allowed between
                   adjacent undercut or underbead concavity indications
                   is 1/2 the length of the longest adjacent indication.

  Misalignment     Misalignment shall not exceed 15% of T, or 0.025",
                   whichever is the lesser.

  Weld Face or     Thinning shall not exceed 15% of T or 0.015",
  Root Concavity   whichever is the lesser.
  or WM Thinning   

  Weld Face or     Reinforcement, or melt-thru, shall not exceed 20% of T
  Root Convexity   or 0.06", whichever is the lesser.
  ---------------- ------------------------------------------------------