**Process Specification for Magnetic Particle Inspection**

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| **Engineering Directorate**                                           |
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| **Structural Engineering Division**                                   |
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| **February 2007**                                                     |
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| ![](media/image1.png)                                                 |
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| National Aeronautics and                                              |
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| Space Administration                                                  |
|                                                                       |
| **Lyndon B. Johnson Space Center**                                    |
|                                                                       |
| Houston, Texas                                                        |
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**Process Specification for Magnetic Particle Inspection**

+--------------------+-----------------------------+-----+-----------+
| **Prepared by:**   | ### **Signature on File**   |     | 02/14/07  |
+--------------------+-----------------------------+-----+-----------+
|                    | Ajay Koshti, ES4            |     | Date      |
+--------------------+-----------------------------+-----+-----------+

+--------------------+-----------------------------+-----+-----------+
| **Approved by:**   | ### **Signature on File**   |     | 02/XX/07  |
+--------------------+-----------------------------+-----+-----------+
|                    | Bradley S. Files,           |     | Date      |
|                    |                             |     |           |
|                    | Chief, Materials and        |     |           |
|                    | Processes Branch/ES4        |     |           |
+--------------------+-----------------------------+-----+-----------+

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

  VERSION     CHANGES                                       DATE

  Baseline    Original version                              7/22/99

  A           Reviewed document per QMS requirements.       12/19/02
              Updated division name, organization codes,    
              and document numbers.                         

  B           Deleted SNT-TC-1A and MSFC-STD-1249. Added    02/14/07
              NASA-STD-5009 and NASA-STD-5019.              

                                                            

                                                            
  ----------- --------------------------------------------- ---------------

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

This process specification establishes the minimum requirements for
magnetic particle inspection of ferromagnetic materials and components.

# **2.0 APPLICABILITY**

This specification is applicable to in-process, final, and in-service
magnetic particle inspections to detect discontinuities that are on or
near the surface of ferromagnetic materials. Magnetic particle
inspection is not applicable to nonferromagnetic metals and alloys.

**3.0 [USAGE]{.underline}**

This specification shall be invoked by including an inspection note on
the applicable engineering drawing or by reference in a Process
Specification, Task Performance Sheet, Discrepancy Report/Material
Review Record, or other appropriate document. The engineering drawing or
referencing document shall specify the criteria by which components are
judged acceptable. Where acceptance criteria are not otherwise specified
the criteria in Section 3.3 shall apply. Other acceptance criteria, such
as those in MIL-STD-1907, may be used as appropriate. When there are
different acceptance criteria for different areas on a component, the
drawing shall be zoned with the acceptance criteria identified for each
zone. If the number of components to be inspected and the amount of
coverage of each component is not specified, all components shall be
examined and shall receive 100 percent magnetic particle coverage.

The standard magnetic particle inspection note for flight hardware and
critical ground equipment is given in Figure 1.

Figure 1.

An example of a magnetic particle inspection note for non-critical
ground equipment using the acceptance criteria in MIL-STD-1907 is given
in Figure 2.

Figure 2.

**3.1 INSPECTION SEQUENCE**

The stage in the manufacturing process where magnetic particle
inspection is performed should be specified on the engineering drawing
or in the referencing document. Final magnetic particle inspection shall
be performed after completion of all manufacturing operations that can
generate surface or near surface discontinuities. These operations
include, but are not limited to, forging, heat treating, plating,
passivation, cold forming, welding, grinding, straightening, machining,
and proof loading. In general, components should be inspected prior to
the application of any coatings. Components heat treated to an ultimate
tensile strength of 180 ksi or higher that are subsequently
electroplated shall be inspected after the electroplating operation.

**3.2 SPECIAL NDE OF FRACTURE CRITICAL COMPONENTS**

When implementation of fracture control requirements necessitates
Special Nondestructive Evaluation (NDE) of a fracture critical
component, the requirement for Special NDE shall appear in the
inspection note as shown in Figure 3. When Special NDE is required, the
specific inspection procedure and inspector shall be qualified in
accordance with Section 7.0.

Figure 3.

**3.3 ACCEPTANCE CRITERIA**

The engineering drawing or referencing document shall indicate the
criteria by which components are judged acceptable. Where acceptance
criteria are not otherwise specified the following criteria shall apply:

a\. [Linear indications]{.underline} -- all linear indications,
regardless of length, shall be cause for rejection of the component.

b\. [Single rounded indications]{.underline} -- a single rounded
indication greater than 0.030 inches in diameter shall be cause for
rejection of the component.

c\. [Multiple rounded indications]{.underline} - two or more rounded
indications each less than 0.030 inches in diameter but separated by
less than 0.030 inches shall be cause for rejection of the component.

**4.0 [REFERENCES]{.underline}**

The following specifications, standards, and handbooks form a part of
this document to the extent specified herein. All documents listed are
assumed to be the current revision unless a specific revision is listed.
In the case of conflict between this specification and the technical
requirements cited in other referenced documents, the requirements of
this document take precedence.

ASTM E 1444 *Standard Practice for Magnetic Particle Inspection*

MIL-STD-1907 *Inspection, Liquid Penetrant and Magnetic Particle,
Soundness Requirements for Materials, Parts, and Weldments*

NASA-STD-5009 Nondestructive Evaluation Requirements for Fracture
Critical Metallic Components

NAS 410 *NAS Certification & Qualification of Nondestructive*

*Test Personnel*

# NASA-STD-5019 *fracture Control Requirements for Spaceflight Hardware*

NASA-STD-5003 *Fracture Control Requirements for Payloads Using the
Space Shuttle*

SSP 30558 *Fracture Control Requirements for Space Station*

The following references were used to develop this process
specification:

SOP-007.1 *Preparation and Revision of Process Specifications (PRC's)*

JSC 8500 *Engineering Drawing System Requirements*

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

Inspection materials shall meet the requirements in ASTM E 1444.

**6.0 [PROCESS REQUIREMENTS]{.underline}**

**6.1 GENERAL**

Magnetic particle inspections shall be performed in accordance with ASTM
E 1444 except as modified by this specification. Unless otherwise
specified, the wet fluorescent particle continuous method shall be used
for flight hardware and critical ground equipment.

**6.2 WRITTEN PROCEDURES**

A detailed written procedure shall be prepared for each part to be
inspected. The procedure shall meet the requirements of this
specification and shall ensure the consistency and reproducibility of
the inspection at the required sensitivity level. General procedures
covering a variety different parts may be used provided they meet the
requirements of this specification and clearly apply to the parts to be
inspected. When general procedures are used, a written part specific
technique shall be prepared. At a minimum, the part specific procedure
or the general procedure and part specific technique shall cover all of
the information required by ASTM E 1444.

For work performed at JSC facilities, written procedures should consist
of Detailed Process Instructions (DPIs) selected for use from the
DPI-6505-XX series of work instructions.

**6.3 FRACTURE CRITICAL COMPONENTS**

Magnetic particle inspection of fracture critical components shall be
performed in accordance with the process requirements in NASA-STD-5009.
The requirements in NASA-STD-5009 not otherwise covered in this
specification are included in the following:

a\. Examination surfaces must be easily accessible with a surface
roughness of 125 RMS or better.

b\. Inspections shall be performed prior to the application of any
coatings.

c\. The wet fluorescent particle continuous method shall be used.

d\. Local magnetic field strength shall be verified using an artificial
flaw shim or a Hall effect probe. When a Hall effect probe is used,
readings shall be correlated with an artificial flaw shim in an
equivalent part location. Pie gages are not acceptable for verifying
field strength.

When Special NDE is specified by the engineering drawing or referencing
document, the inspection procedure and inspector shall be qualified in
accordance with Section 7.0.

**7.0 [SPECIAL NDE QUALIFICATION]{.underline}**

Use of Special NDE in accordance with NASA-STD-5019, NASA-STD-5003 or
SSP 30558 requires formal demonstration of the capability to detect
flaws at least as small as the critical initial crack size for the
specific component to a 90/95 detection level. Each procedure, procedure
application, and operator must demonstrate the required capability.
Requests for Special NDE qualification shall be directed to the JSC
Materials and Processes Branch (ES4).

## **8.0 [DEVIATIONS AND WAIVERS]{.underline}**

Any deviations or waivers regarding the use of this process
specification shall be requested in writing. This request shall be
directed to the JSC Materials and Processes Branch (ES4) with the
appropriate justification and rationale. A written response will be
provided upon such a request.

**9.0 [TRAINING AND CERTIFICATION OF PERSONNEL]{.underline}**

Personnel performing magnetic particle inspections shall be qualified
and certified in accordance with NAS 410. Personnel making accept/reject
decisions shall be certified to at least Level II. Personnel performing
inspections on fracture critical components shall, at a minimum, be
certified to Level II.

For work performed at JSC facilities, these requirements may be
satisfied by the training and certification of personnel per the
TI-6505-XX series of Training Instructions (TIs).

**10.0 [DEFINITIONS]{.underline}**

90/95 The point where the 95% lower confidence bound on the

Probability of Detection (POD) vs. flaw size curve crosses 90% POD or
90% POD with 95% lower confidence bound.

Discontinuity An intentional or unintentional interruption in the
physical structure or configuration of a material or component that may
be detectable by nondestructive testing; a flaw. Discontinuities are not
necessarily rejectable.

Final Inspection The final inspection performed for the acceptance of
the component.

Fracture Critical Classification which assumes that fracture or failure
of the

Component component resulting from the occurrence of a crack will result
in a catastrophic hazard. Fracture critical components will be
identified as such on the engineering drawing.

Indication Evidence of a discontinuity that requires interpretation to
determine its significance.

In-Process Inspections which occur during manufacturing before a
component is in final form.

In-Service Inspections performed on components that are in use or
storage.

Linear Indication Penetrant indication with a length to width ratio of
3:1 or greater.

Rounded Penetrant indication with a length to width ratio of less than

Indication 3:1.

Special NDE A fracture control term denoting nondestructive inspection
personnel, procedures, and equipment with a demonstrated capability to
reliably (90/95) detect flaws smaller than those normally detected by
typical procedures.