NBSIR 74-425

Investigation of G-74 Currency Plate

Tensile Properties and Performance

I. J. Feinberg and T. R. Shives

Mechanical Properties Section

Metallurgy Division

Institute for Materials Research

National Bureau of Standards

Washington, D. C. 20234

January 1974

Test Report

Prepared for Electrolytic Section Bureau of Engraving and Printing

Department of the Treasury

Washington, D. C. 20226
J
NBSIR 74-425

INVESTIGATION OF G-74 CURRENCY PLATE

TENSILE PROPERTIES AND PERFORMANCE

I. J. Feinberg and T. R. Shives

Mechanical Properties Section

IVletallurgy Division

Institute for Materials Researcli

National Bureau of Standards

Washington, D. C. 20234

January 1974

Test Report

"This document has been prepared for the use of the Electrolytic Section, Bureau of Engraving and

Printing, Department of the Treasury, Washington, D. C.

Responsibility for its further use rests with that agency. NBS requests that if release to the general

public is contemplated, such action be taken only

after consultation with the Office of Public Affairs

at the National Bureau of Standards.

Prepared for Electrolytic Section Bureau of Engraving and Printing

Department of the Treasury

Washington, D. C. 20226

U. S. DEPARTMENT OF COMMERCE, Frederick B..Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

TABLE OF CONTENTS

Page

SUMMARY iv

1. INTRODUCTION 1

1.1 History 1

1.2 Purpose 1

2. PLAN OF THE INVESTIGATION 1

3 . MATERIAL

.

3

3.1 Plate Preparation 3

3.2 Material Submitted 3

4 . EXPERIMENTAL WORK 3

4.1 Tensile Properties 4

4.2 Chemical Analysis 4

4.3 Thickness and Hardness Measurements 4

4.4 Microscopic Observations 4

4.5 Plate Mileage Tests 4

5. INVESTIGATION RESULTS AND DISCUSSION 5

5.1 Chemical Analysis 5

5.2 Thickness Measurements 5

5.3 Hardness Measurements 5

5.4 Microscopic Observations 6

5.5 Tensile Properties 6

5.6 Plate Performance in Mileage Tests 7

5.6.1 Mileage versus SNSR additions and

tensile properties 7

5.6.2 Nature and location of failures in

mileage tests 8

i •

6. CONCLUSIONS

7 . ACKNOWLEDGMENTS

REFERENCES

TABLES

1. Constants and Variables in the Technique Employed

in the Preparation of Electroformed Currency

Plate Material

2. Chemical Composition of Selected Plates

3. Results of Blank Plate Thickness Measurements

4. Results of Face Plate Strip Thickness Measurements .

5. Results of Back Plate Strip Thickness Measurements .

6. Results of Blank Plate Hardness Measurements

7. Results of Face Plate Strip Hardness Measurements ..

8. Results of Back Plate Strip Hardness Measurements ..

9. Blank Plate Tensile Properties

10. Tensile Properties of Face Place Strips

11. Tensile Properties of Back Plate Strips

12. Average Tensile Properties of Selected Face and

Back Plate Strips Versus Plate I^ileage

FIGURES

1. Sketch Showing Individual Note Locations on a Currency Plate

2. Cutting Map Showing Location of Tensile,

Metallographic and Chemical Analysis Specimens . . .

3. Effect of SNSR Addition in Electroforming on

Hardness of Strips.

4. Photomicrographs Showing Structures in Blank

Plates, Ic and 2c.

ii

FIGURES (Continued)

5. Photomicrographs Showing Structures in Specimens

Cut from Face and Back Plate Strips

6. Sketch Showing Nature and Approximate Location

of Face Plate Failures

7. Sitetch Showing Nature and Approximate Location

of Back Plate Failures

SUMFARY

This investigation revealed that a desirable uniformity

in composition, thickness, hardness, microstructure and

tensile properties is attained from plate to plate in

electroforming . Tests programed to determine whether an

increase in plate yield and tensile strengths would afford

an improvement in plate service life were inconclusive due

to the scatter in the service lives obtained in the limited

number of tests conducted at various strength levels.

Fatigue cracking, apparently due to excessive vibration and

cyclic stressing, .was found to be the chief cause of plate

failure in the tests. It is unlikely that significant

improvements in the service life of G-74 currency plates

can be attained until conditions leading to excessive

vibration and cyclic stressing in the G-74 presses are

remedied

iv

•Investigation of G-74 Currency Plate

Tensile Properties and Performance

1 . INTRODUCTION

1 . 1 History

The Bureau of Engraving and Printing (BU E&P) has been

concerned about the short service life of a considerable

number of currency plates on their G-74 presses. A comprehensive examination was conducted for Bu E&P on plate No.

41812, a plate that failed because of blistering. The

results of this examination are given in reference [1] . The

failure of G-74 currency plates by blistering was attributed

largely to mechanical problems which arise during operation

of the presses. It was evident too, from observations in

the course of this investigation, that fatigue cracking, the

overall chief cause of reduced plate service life, was also

largely due to mechanical problems.

1 . 2 Purpose

The purpose of this investigation was to determine if

changes in the mechanical properties of currency plates

could increase their service life. A higher plate yield

strength had been suggested by NBS as possibly affording an

improvement in service life, particularly in reducing the

incidence of fatigue cracking [2] , It was further suggested

to Bu E&P that a quality control program for the production

of electroformed plates that would include the collection

of statistical data on mechanical properties be conducted

in cooperation with NBS personnel I3J . Bu E&P agreed to both

approaches in search of an improvement in plate service life.

The results of an examination of a limited amount of material

submitted to NBvS by Bu E&P under a plan proposed by NBS are

herein reported.

2. PLAN OF THE INVESTIGATION

Three general approaches were suggested by NBS and

accepted by Bu E&P. These are as follows:

1. Consider the use of a higher yield strength

material.

2. Establish a quality control program for the

production of the electroformed nickel plates

which would include the collection of statistical

data on mechanical properties. This would be done

in cooperation with NBS personnel.

1

3. Monitor the mechanical operation of the G-74

presses recording pertinent information such

as hov; often the plates are tightened, mileage

v/hen cracks first appeared, final plate mileage, etc.

Implementation of these approaches involved the following:

a. Testing and evaluation data from specially prepared

blank plates and from specially prepared face and

back plates subjected to mileage tests.

b. Keeping the follov;ing constant in the preparation

of plates:

(a) ph of electrolyte

(b) Electrolyte temperature

(c) Current density

c. Varying amount of hardening agent (SNSR) 2 of electroforming bath.

d. Limiting tests to one press for face plates; to

another for back plates.

e. Observing any mechanical or operational changes that

might affect mileage on the presses used.

f. Conducting appropriate chemical analyses, thickness

measurements, microscopic observations, and tensile

and hardness tests on specimens from blank, face

and back plates.

g. Comparing blank plate hardness and tensile properties

with face and back plate hardness and tensile

properties.

h. Evaluating hardness and tensile property data obtained

for face and back plates for possible correlation with

mileage and with the nature and location of failures

on these plates.

Mileage is a term used by Bu E&P to denote the number of

complete sheet impressions obtained from an individual

plate in currency printing.

SNSR is the abbreviation for the sulfamate nickel stress

reducer used by Bu E&P as the hardening agent.

2
£'
3 . MATERIAL

3 . 1 Plate Preparation

Bu E&P prepared twenty-tv/o plates which included two

blanks, eleven currency face and nine currency back plates.

Constants and variables in the technique employed in the

electrof orming of these plates are given in Table 1.

3 . 2 Material Submitted

The two blank plates were submitted in their entirety

and two strips, nominally 0.75 inch wide, were submitted from

each of the face and back plates for tests. The strips were

stamped with either a letter, T, or a letter, B, and were

cut from the respective top or bottom edges of the plates as

they were positioned in the electroforming tank. None of the

material had been chromium plated, as-received.

Figure 1 is a sketch showing individual note locations

and the leading and trailing edges of a currency plate with

respect to the positions of these edges on a printing

cylinder and the direction of cylinder rotation. Note that

T and B, representing the original top and bottom positions

of a plate in the electroforming tank, are located at angles

of 90 degrees counterclockwise to the leading edge and

trailing edge, respectively

4 . EXPERIMENTAL WORK

Experimental work by the Mechanical Properties Section

of NBS in this investigation was limited to obtaining data

on material properties. Conventional chemical analyses were

conducted to determine whether any undesirable impurities

were present in the material. Thickness measurements were

made to determine if there were any significant localized

differences in plate thicknesses. Hardness and tensile

properties were obtained to determine what effects variations

in the hardener addition used in plate preparation had on

these properties. The location and nature of plate damage

that terminated the service life of currency face and back

plates and the mileages obtained were logged by Bu E&P

personnel. Metallographic examinations were made of specimens

from blank plates and from selected face and back plates

exhibiting significant differences in mileage.

3

4 . 1 Tensile Properties

The tensile properties of blank plates Ic and 2c were

obtained from ten specimens cut from each plate. The

identifications and locations of these specimens are given in

Figure 2. The letters L and T in the specimen identifications

indicate that the specimens were cut from these blank plates

so that their long axes would be aligned parallel or transverse to the direction of plate rotation, respectively, had

these plates been regular basso printing plates. Face and

back plate tensile properties were attainable by NBS only

from specimens cut from the face and back plate strips

submitted. These tensile specimens necessarily were cut so

that their long axes were transverse to the direction of

cylinder rotation. Tensile test specimens were machined using

the as-received thickness (approx. 0.030 inch), and a 0.500

inch width and 2 inch gage length in the reduced section.

They were tested in accordance with ASTf^ Designation E8-66.

4 . 2 Chemical Analysis

Chemical analyses by spectrometric or combustion methods

v/ere performed on samples cut from the areas of blank plates,

Ic and 2c, shov/n in Figure 2, and from strips from plate

Numbers 42233B and 42248B.

4 . 3 Thickness and Hardness Neasurem.ents

Thickness and hardness measurements were made on each

of the ten tensile test specimens cut from both Ic and 2c.

Face and back plate thickness and hardness measurements were

also made on tensile test specimens cut from strips submitted

by Bu ESiP.

4 . 4 Microscopic Observations

Specimens were cut from the areas of plates Ic and 2c,

shown in Figure 2, for metalloaraphic examination. Fetallographic examinations were conducted on specim.ens cut from

strips of face plates numbered 42233, 42239, 42245 and 42248 and

from strips of back plates numbered 7637, 7G39, 7645 and 7646.

4 . 5 P late Mileage Tests

Currency face plates subjected to mileage tests v/ere

mounted on the G 74-101 press and currency back plates on the

G 74-104 press. The pressures in each press were adjusted

according to normal 3u E&P procedures to obtain satisfactory

printing impressions. Normally a higher pressure is required

in printing face notes than in printing back notes. Both

presses were run at speeds to obtain 7000 sheets per hour.

4

5. INVESTIGATION RESULTS AND DISCUSSION

5 . 1 Chemical Analysis

Results of the chemical analyses of samples from plates

Ic, 2c, 42233 and 42248 are given in Table 2. The analyses

indicate a similarity in the composition of the four samples.

Impurity contents are low with the exception of cobalt (0.65

to 0.94%). The NBS Corrosion and Electrodeposition Section

does not consider the cobalt contents as being detrimental.

5.2 Thickness Measurements

The results of thickness measurements on the blank plates,

face plate strips, and back plate strips are given in Tables

3, 4, and 5, respectively. A considerable number of the

measurements in all three groups were outside the tolerance

limits. Hov^ever , most of the measurements that fell outside

of the tolerance limits did so by an amount small enough to

fall within the measurem.ent error. The thickness measurements

of only two strips, 42233T and 42235T, were considered to be

out of tolerance to an appreciable amount.

Thickness measurements v/ere made in widely distributed

areas of blank plates, Ic and 2c, to determine whether there

were any localized differences. The differences found are

not considered to be significant. Table 4 shows the spreads

in thickness between bottoms and tops of plates. If the

Bu E&P 0.03000 ± 0.00025 limits are used as a criterion, then

the differences between bottom and top thicknesses of some of

these plates would be outside of tolerance limits, but again

the amounts are within experimental error. Moreover, NBS has

no evidence that similar spreads, which then could be a matter

of concern, were present in adjacent plate note areas.

5.3 Hardness Measurements

The results of Rockwell 15T (R15T) hardness measurements

on the blank plates, face plate strips, and back plate strips

are given in Tables, 6, 7, and 8, respectively. A two point

spread (88-90 R15T) v/as observed in plate Ic and a three

point spread (88-91 R15T) in plate 2c. Probably the only

appreciable localized hardness differences found in the

respective plates in comparing individual hardness readings

with average values were a high reading (90 R15T) adjacent to

the K^-A-^ notes of plate Ic and a low reading (88 R15T)

adjacent to the A4-E2 notes of plate 2c. In comparing hardness

values found in both plates no significant pattern of localized

differences covering a large area was observed. Interestingly,

5

an increase in the hardener addition from 25 ml for plate Ic

to 50 ml for plate 2c resulted in only about a one point,

R15T, increase in the average hardness of the latter. Tables

6 and 7 indicate that an increase of the hardener additions

from 20 ml to 75 ml resulted in an increase in the hardness

of strips from about 89 R15T to about 91.5 R15T.

Figure 3 shows, graphically, the effects of the hardener

addition on the hardness of strips from face and back plates.

There is an apparent exponential increase in hardness with

increase in the hardener addition. However, paucity of data

points and scatter in the available data are great and therefore preclude the derivation of a reliable curve which would

indicate the amount of hardener addition needed to achieve a given hardness.

5 . 4 Microscopic Observations

Blank plate microstructures are shown in Figure 4 and

face and back plate microstructures in Figure 5. The columnar

grains in each view are normal for electroform.ed nickel. A

50 ml SNSR addition in the electroforming process produced a finer grain size than did a 25 ml addition, as shown in

Figure 4. Similarly, 75 ml additions produced finer grain

sizes than 20 or 25 ml additions, as shown in Figure 5.

Microscopic examination of face and back plate strip specimens revealed no structural discontinuities that could

affect the mileages of the plates from which they were cut.

5 . 5 Tensile Properties

Tensile properties of the blank plates are given in

Table 9. Analysis of these data indicated no appreciable

directional differences; i.e., the tensile properties of

specimens oriented parallel to the A1-D2 direction were found

to be generally quite similar to those oriented at a right

angle to the A1-D2 direction. While yield strength values

exhibited greater scatter than did tensile strength values,

the scatter of both is considered to be v;ithin tolerable

limits. No appreciable localized differences in yield

strength or tensile strength were found. Ductility as

measured by percent elongation and the ratio of yield strength

to tensile strength was found to be quite uniform throughout

plates Ic and 2c with the exception of the slightly greater

ductility found in the H2-D2 note areas of both plates,

Ic and 2c » Doubling the SNSR addition in electroforming of

the blank plates from 25 to 50 ml resulted in average

increases of approximately 10% in yield strength, 8% in tensile

strength, and 1% in the ratio of yield strength to tensile

strength. Elongation decreased by about 27%.

6

Tensile properties of face plate and back plate strips

are grouped in Tables 10 and 11, respectively. These data

indicate that the average yield and tensile strengths of

bottom (B) strips from both groups are significantly higher

than that of top (T) strips. There does not appear to be

any significant difference in ductility as determined by

averaging the percentages of elongation and the ratios of

yield strength to tensile strength values of B and T strips.

The data in both Tables 10 and 11 indicate that generally

a progressive increase in yield strength and tensile strength

and a progressive decrease in ductility of the plate strips

resulted from progressive increase of the SNSR addition in

electroforming

5 . 6 Plate Performance in Mileage Tests

5.6.1 Mileage versus SNSR additions and tensile properties

The mileage of individual face and back plates are

given in Tables 10 and 11, respectively. Face plate mileages

ranged from a low of 129,163 to a high of 834,963. Omitting

the low mileages obtained for plate no's. 7640 and 7642,

adjusted back plate mileage ranged from a low of 205,811 to a high of 732 , 396 .-'- An average mileage of 501,874 was obtained

for face plates on the G 74-101 press and an adjusted average

mileage of 361,737 for back plates on the G 74-104 press.

The high face plate mileage, 834,963, was obtained from a plate having a 75 ml SNSR electroforming bath addition, whereas the high back plate mileage, 732,396, was obtained from a

plate having a 25 ml SNSR bath addition.

There appears to be no advantage in increasing yield

strength and tensile strength through increase of the SNSR

addition in plate preparation. The data in Table 12 indicates

a similarity in the average mileages obtained from face plates

made with 25 and with 75 ml SNSR additions. The 75 ml

addition resulted in significantly higher yield strength and

tensile strength. Table 12 also indicates that a significantly

greater average yield strength and tensile strength were

obtained from back plates made using a 75 ml bath addition.

In this case, average mileages obtained from the 25 ml addition

plates were approximately 50% greater than those obtained from

the 75 ml addition plates.

The low mileages obtained for plate no's. 7640 and 7642 were

due to mechanical malfunction (rigging ball-up) . They were

not considered to be representative of mileages that could

be obtained if the malfunction had not occurred and were

accordingly omitted.

7

5.6.2 Nature and location of failures in mileage tests

Figures 6 and 7 are sketches intended to indicate

the nature and approximate location of failures of face and back

plates, respectfully. This information has been obtained from

pertinent record sheets submitted by Bu E&P.

Fatigue cracking was the chief cause of face plate failure.

Fatigue cracking occurred between the bottom margins of the H^f

D2 , H4 and D4 notes and the trailing edges of these plates and

also along the trailing edge pitch line of these plates.

There was only one instance, each, of a dimple, of rippling

and blistering, and of a ball-up (rippling) failure. Face

plate failures were largely concentrated adjacent to the H2

and D2 notes.

Fatigue cracking was also the chief cause of back plate

failure. Fatigue cracks occurred along the leading edge pitch

line adjacent to the E3-A3 notes and between the top margins

of the E3 and A3 notes and the leading edge pitch line of the

back plates. Fatigue cracking also occurred adjacent to the

G4 , H4 and C2 notes and adjacent to the trailing edge pitch

line, as shown in Figure 4. There were three instances of

back plate ball-up and rippling failure.

Above average mileage was obtained from three face plates

that failed due to fatigue cracking and below average mileage

from five face plates all of which failed by fatigue cracking.

Above average mileage was obtained from one face plate that

blistered and another that dimpled. Above average mileage was

obtained from three back plates that failed due to fatigue

cracking and below average mileage from four back plates that

failed due to this cause. Premature failure of two back plates

occurred when the printing cylinder rigging became loose and

caused a ball-up on these plates.

6. CONCLUSIONS

Chemical analyses indicated a similarity in the composition of samples from four plates that v/ere analyzed. No

detrimental impurities were found and it appears from, these

analyses that a desirable uniformity in composition is

attained from plate to plate in electroforming

All material examined microscopically V7as observed to be

sound from the standpoint of microstructure . While the

observations made were limited in scope, it is considered

that uniform, good quality is achieved in plate production

from day to day.

8

Judging from thickness measurements made on the blank

plates , and measurements covering ten separate note areas

on each plate, sufficient uniformity in plate thickness,

in the note areas, is attained in electroforming

Doubling the SNSR addition in the electroforming of

blank plates from 25 to 50 ml resulted in an average increase

of only one R15T hardness point (89 R15T to 90 R15T)

Increasing the SNSR addition from 20 ml to 75 ml resulted in

the small increase in the average hardness of strips from 89

R15T to about 91.5 R15T. It may be assumed that increases

in average hardness of a similar magnitude occurred in the

note areas of the plates from which the strips were obtained.

It is understood that Bu E&P made hardness measurements at

the centers of the face and back plates from which related

strips were submitted to NBS . The hardness values obtained

by Bu E&rP at plate centers were generally one to two Rockwell

15T points higher than those obtained by NBS on related plate

bottom and top strips. The hardness differences could be due

either to a difference in the techniques employed in hardness

measurement or to the possibility that plate bottom and top

strip areas are actually lower in hardness than those at the

center. Judging from hardness measurements made on the blank

plates, no significant pattern of localized hardness difference between note areas of substantial size occurs in the

electroforming of plates.

The investigation revealed that generally a progressive

increase in the yield and tensile strengths and a progressive

decrease in the ductility of plate material resulted from a progressive increase of the SNSR addition in electroforming

Judging from results obtained from blank plates no appreciable

directional or localized differences in the yield strength,

tensile strength or ductility properties of plates occur in

their production.

A tremendous scatter in the results obtained from

individual plates was observed in mileage tests. This was

true for both face and back plates and for plates in both of

these categories that had been produced using the same SNSR

addition in electroforming . A broad scatter in plate mileage

is a problem occurring in currency printing on all

presses using plates produced by the currently standardized

Bu E&P electroforming technique. Apparently, the scatter

occurring in the mileage tests in this investigation is a reflection of this inherent problem. The greater plate yield

and tensile strengths gained by the increase of the SNSR

addition in electroforming apparently resulted in no improvement in plate mileage. However, the mileage tests were

severely limited in the number of plates tested in each SNSR

addition category. Each category exhibited great scatter.

9
\

I
Accordingly, recognizing that greater attention must be given

to the scatter problem in mileage testing, the conclusion

that higher plate yield strength and tensile strength afford

no improvement in mileage could possibly be reversed if the

mileage tests were made more comprehensive by testing a larger number of plates in each SNSR addition category.

Fatigue cracking was the chief cause of plate failure

on both presses and blistering a secondary cause. Greater

mileages, overall, were obtained for face plates which were

run on the G 74-101 press than those obtained from back

plates on the G 74-104 press. As previously noted, a greater pressure is exerted in printing face plates than in

printing back plates and one might, therefore, expect greater

mileage from the G 74-104 press. The explanation for the

lower mileages obtained on the G 74-104 press may be that

this press is subjected to more cyclic vibration and stressing,

the primary causes of fatigue cracking and a probable factor

in blistering. Vibration due to bearing wear, cylinder

unbalance, gear drive enevenness, faulty mounting, etc., may

be greater in this press than on the G 74-101 press. The

NBS Vibration Section has suggested that these mechanical

conditions be studied in an analysis of the vibration

problem [4]

It is the opinion of the authors that no improvement

in the mileage of G-74 currency plates can be realized by an

improvement of tensile properties until conditions leading to

excessive vibration and cyclic stressing in the G-74 presses

are remedied.

ACKMOWLEDGNENTS

The metallographic specimens were prepared by Mr. L. C.

Smith, Mechanical Properties Section, Metallurgy Division.

The photographic prints were also made by Mr. Smith.

REFERENCES

[1] "Examination of Failure of G-74 Currency Face Plates",

NBS Report No. 312.01/52, dated October 3, 1972.

[2] Ibid, page 8. Fatigue Properties.

[3] Ibid, page 11. Recommendations.

[4] "Discussion of Bureau of Engraving and Printing Dollar

Bill Plate Failures", NBS Vibration Section, Mechanics

Division Memorandum by John D. Ramboz, dated

December 14, 1972.

10

Table 1. Constants and Variables in the Technique Employed

in the Preparation of Electroformed Currency

Plate Material

Type of Plate

Plate No.

North (N) or South (S)

Placement in

Tank No. 4 Electrolyteph Temp. Peg. C.

SNSR

Current Density, Addition

Amp ' s ./so . ft. Ml

Blank

Face

Back

Ic S 4 . 5 50 50 25

2c S 4 . 4 50 50 50

42233 - N 4 . 5

5'0' 50 20

42235 N 4 . 5 50 50 25

42237 N 4 . 5 50 50 25

42238 s 4 . 5 50 50 25

42239 N 4 . 5 50 50 25

42241 N 4 .45 50 50 65

42242 s 4 .45 50 50 65

42244 N 4 .48 50 50 75

42245 S 4 .48 50 50 75

42248 N 4 0 50 50 75

42249 S 4 .0 50 50 75

7637 s 4 5 50 50 20

7638 s 4 5 50 50 25

7639 N 4 5 50 50 25

7640 S 4. 5 50 50 25

7642 N 4 . 4 50 50 60

7643 S 4 , 4 50 50 60

7644 N 4 . 4 50 50 50

7645 N 4 . 48 50 50 75

7646 S 4. 48 50 50 75
,03 0?

v" ^

Or00

"• :^ •- sOil 0 ' :

C50 c 0 .

t.

0^^

i.e.
Table 2. Chemical Composition of Selected Plates

Element Ic 2c 42233B 42248B

% % % % Carbon 0. 01 -< <0 . 01 < 0 . 01 < 0. 01

Sulfur 0 . 005 0. 004 0. 004 0. 004

Iron 0. 01 0 . 01 T < 0. 01 T < 0. 01

Copper < 0. 001 <; 0. 001 < 0 . 001 < 0 . 001

Zinc ND < 0 . 005 ND 0. 005 ND < 0. 005 ND < 0. 005

Chromium ND ' 0. 005 ND 0 . 005 ND < 0. 005 ND < 0. 005

Lead ND < 0. 005 ND 0 . 005 ND < 0. 005 ND < 0. 005

Aluminum 0. 009 ND 0. 005 ND < 0. 005 ND < 0. 005

Cobalt 0 . 69 0. 65 0. 94 0. 92

T - Trace

ND - Not detected

Table Results of Blank Plate Thickness Measurerients

Plate

No,

Measurement

Location

Nearest Notes

Plate

Thickness

Inch

Bu E&P

Tolerance

Inch

Ic

2c

E3-A3

H4-D4

A4-E2

^1-^1

4 4

^1-«1

E3-A3

E^-A^

4 4

A4-E2

F3-G3

^1-^1

F4-G4

B2-C2

^1-«1

0.0303

0. 0303

0.0304

0.0304

0.0303

0. 0301

0.0302

0.0303

0.0304

0.0303

0.0302

0. 0304

0.0302

0.0304

0 . 0303

0.0303

0.0302

0.0303

0.0303

0,0303

0. 03000

± 0.00025

0. 03000

± 0.00025

0. 03000

± 0.00025

0 . 03000

± 0.00025

0. 03000

± 0.00025

0.03000

± 0.00025

0. 03000

± 0.00025

0.03000

± 0.00025

0. 03000

± '0 . 00025

0 . 03000

± 0.00025

0.03000

± 0.00025

0.03000

± 0.00025

0.03000

± 0.00025

0 . 03000

± 0.00025

.0 . 03000

± 0.00025

0.03000

± 0.00025

0 . 03000

± 0.00025

0.03000

± 0.00025

0. 03000

± 0.00025

0.03000

± 0.00025

fable 4. Results of Face Plate Strip Thickness Measurements

Strip

Plate

No.

42233

42233

42235

42235

42237

42237

42238

42238

42239

42239

42241

42241

42242

42242

42244

42244

42245

42245

42248

42248

42249

42249

Origin

B - Plate

Bottom

T - Plate

Top

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

Measurement

Location

on Strip,

Nearest Notes

°l-^2

H3-E4

°l-^2

H3-E4

H3-E4

D^-A^

H3-E4

D,-A2

H3-E4

D^-A^

H3-E4

D^-A^

H3-E4

D,-A2

H3-E4

D,-A2

H3-E4

D,-A2

H3-E4

Strip

Thickness

Inch

0.0303

0.0313

0. 0301

0. 0*"3 03

0.0300

0. 0298

0.0300

0.0300

0.0300

0.0299

0. 0302

0.0297

Difference

Inch

0. 0300

0.0296

0 . 0295

0.0301

0.0299

0. 0294

0.0301

0.0295

0.0303

0. 0299

0.0010

0. 0007

0.0002

0.0001

0.0005

0.0004

0.0006

0.0005

0.0004

0. 0004

Bu E&P

Tolerance

Inch

0. 03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0. 03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0. 03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

Table 5. Results of Back Plate Strip Thickness Measurements

Strip

Plate

No.

7637

7637

7638

7638

7639

7639

7640

7640

7642

7642

7643

7643

7644

7644

7645

7645

7646

7646

Origin

B - Plate

Bottom

T - Plate

Top

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

B

T

Measurement

Location

on Strip,

Nearest Notes

°l-^2

H3-E4

D,-A2

H3-E4

H3-E4

H3-E,

D,-A2

H3-E4

°l-^2

H3-E4

D,-A2

H3-E4

D^-A2

H3-E4

^1-^2

H3-E4

Strip

Thickness

Inch

0.0294

0.0305

O.C»299

0.0302

0.0303

0.0299

0.0300

0.0299

0.0300

0.0299

0 . 0300

0.0296

0.0302

0.0299

0.0300

0.0299

0.0300

0.0295

Difference

Inch

0.0011

0.0003

0 .0004

0.0001

0.0001

0.0004

0.0003

0.0001 •

0.0005

Bu E&P

Tolerance

Inch

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0. 00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0.03000

±0.00025

0. 03000

±0.00025

0.03000

±0.00025

Table 6. Results of Blank Plate Hardness Measurements

Plate

No

Ic

Measurement

Location

Nearest Notes

SNSR

Addition

m

Rockwell 15T

Hardness

Note Area

E3-A3 25 90

E^-A^ 88

88

< 88

A4-E2 89

89

^1-^1 89

F4-G4 89

B2-C2 89

G,-H, . 89

Average 88,

2c E3-A3

E^-A^

H4-D4

H2-D2

A4-E2

F3-G3

^1-4

F4-G4

B2-C2

^1-«1

50 90

91

91

90

88

90

91

90

90

91

Average 90.2

Table 7. Results of Face Plate Strip Hardness Measurements

Origin

B - Plate Measurement

Strip Bottom Location

Plate T - Plate on Strip

No. Top Nearest

42233 B D^-A2

42233 T ' "3-^4

42235 B 42235 T H3-E4

42237 B D^-A2

42237 T H3-E4

42238 B °r"^2

42238 T H3-E4

42239 B

42239 T H3-E4.

42241 .B D^-A^

'42241 T H3-E4

42242 B °1"^2

42242 T H3-E4

42244 B D^-A2

42244 T H3-E4

42245 B D^-A2

42245 T H3-E4

42248 B °l-^2

42248 T H3-E4

42249 B D^-A2

42249 T H3-E4

Rockwell 15T Hardness

SNSR Bu E&P

Addition Plate Center

'^''1 Strip Measurement

20 90 90

2Qt 89 90

25 90 90

25 90 90

25 90 91

25 90 90

25 91 90

25 89 91

25 90 91

25 89 91

65 91 93

65 90 92

65 91 92

65 90 92

75 90 93

75 91 93

75 91 93

75 90 92

75 92 94

75 92 93

75 92 92

75 92 93

Table 8. Results of Back Plate Strip Hardness Measurements

Strip

Plate

No.

Origin

B - Plate

Bottom

T - Plate

Tod

Measurement

Location

on Strip

Nearest Notes

Rockwell 15T Hardness

SNSR Bu E&P

Addition Plate Center

I'l Strip .Measurement

7637

7637

B

T

^1-^2

H3-E4

20

20

90

88

90

90

7638

7638 H3-E4

25

25

89

90

91

91

7639

7639

B

T

D,-A2

H3-E4

25

25

90

89

91

91

7640

7640

°l-^2

H3-E4

25

25

90

89

90

91

7642

7642

B

T H3-E4

60

60

91

90

92

92

7643

7643

B

T

D,-A2

H3-E4

60

60

90

90

91

92

7644

7644

°l-^2

H3-E4

50

50

91

90

92

92

7645

7645

^1-^2

H3-E4

75

75

91

91

93

93

7646

7646

B

T

D^-A2

H3-E4

75

75

92

91

93

93
(

V-
Table 9- Blank Plate Tensile Properties

Blank

Plate Specimen

NO , Number

Ic Ll-1

Ic L2-1

Ic L3-1

Ic L4-1

Ic L7-1

Ic Average

Ic T5-1

Ic T5-2

i D X ±c i D z

i.C i / X xc Average

Overall

2c Ll-1

2c L2-1

2c L3-1

2c L4-1

2c L7-1

2c Average

2c T5-1

2c T5-2

2c T6-1

2c Te-2

2c T7-1

2c Average

Overall

2c Average

Nearest

Notes

^3 ^3

^4 ^2

B^-C^

^4-^4

gI-eI

E -A

E^-A^

H -D

F -G

B^-C^

^4-^4

bI-cI

gI-eI

Yield

Strength,

(Y.S.)

psi

55782

62329

60135

57237

58108

58-)l8

59732

58725

61486

56250

58054

58849

58784

66216

64094

66327

61589

65646

64774

66327

65101

63542

66776

59459

64241

64508

Tensile

Strength

,

(T.S.)

psi

83741

83699

83784

82566

83378

83434

85034

84631

84392

81842

83893

83958

83696

91351

90805

90884

89073

89932

90409

91293

92752

91319

89934

89662

90992

90700

Ratio

Y.S.

T.S .

0.67

0.74

0.72

0. 69

0.70

0.70

0.70

0.69

0.73

0.69

0.69

0.70

0.70

0.72

0.71

0.73

0. 69

0.73

0.72

0.73

0.70

0.70

0.74

0.66

0.71

0.71

Elongation

in 2 Inches

Percent

13

14

14

17

14

14

14

14

14

15

14

14

14

11

11

10

14

10

11

11

11

10

13

12

11

11

Table 10. Tensile Properties of Face Plate Strips

Yield Tensile

Strip

Mo

1

SNSR

Addition

Ml

Strenath

,

(Y.S.)'

S X

Strenath

,

(T.S.)

^ 0 JRatio

Y.S.

rp c

Elongation

in 2 Inches

U 01" <i T*l "H Plate

1*1 X X t; ct U 42233

42233

B

T

20

20

61258

56954

90728

82119

0.68

0.69

13

15

42233 B+T

2 20 59106 86424 0.685 14 X129163 ^ ^ X w -J 42235

42235

B

T

25

25

59459

57843

• 85135

81046

0.70

0.71

10

14

d 9 7 ^ B+T

2

R f; t: 1 J 0 C J X 0R 7 n Q r> J u y un 7 n X1 z9 4'1 J X1 X14*« X1

42237

42237

B

T

25

25

60473

55822

88108

83425

0 . 69

0.67

11

12

B+T

2

J 0 is Q 7 r c 0 D / 0 D U . CO XX11 . D

T R 7 ^ ^ 1^

42238

42238

BT

25

25

62759

61644

90828

84932

0.69

0.73

10

12

4 ^ Z9 T p J 0 B+T

2 c 9 9 n 9 0 ^z u z Q 7 R H r> 0 / 0 0 u

n 71 u . / X X1 X1 T R7 ^ c JO /ODD

42239

42239

B

T

25

25

78472

59247

86389

83904

0 . 91

0.71

11

13

4 9 9 T Q 1 z z 0 y B+T

2 D 0 0 D U 0 D X 'i t3 n HI xz1 9 0fl Z9 9 n 7 D Z U / 42241

42241

B

T

65

65

66887

60959

94834

87877

0.70

0.69

9 12

•t ^ ^ X B+T

2 D 0 ^ Z J Qly X T^ DO^ nu • D Qy J XinU . 3^ / U J ** X 0

4224 2 42242

B

T

65

65

68151

64236

958 90

90278

0.71

0.71

8 10

4 ? ? 4 9 B+T

2 D U X ^ *t -7 0 U 0 *4 U . / X q J *3 U 0 J U 42244

42244

BT

75

75

69310

73510

94138

98344

0 .74

0.75

11

8 42244 B+T

2 75 71410 96241 0.745 9.5 575080

42245

42245

BT

75

75

73129

68403

100000

93333

0.73

0.73

8

9 42245 B+T

2 75 70766 96666 0.73 8 . 5 834963
': S.

J

,.1 Li

'J

; X ;5 ,.

« c I- C

e ^ x.f^

V XX'- X X

j, : h X
Table 10. Continued

Yield Tensile

SNSR Strength

,

Strength, Ratio Elongation

C +- T- i n

^

i^QQ. i L. ± on ^ i . 0 .

V1.0.Q IT J. due

No , Ml psi psi T.S . Percent Mi leaae

4H

?^ ^9 4H SO IdR / J J 0 J i1 nU JR D V U

Q

0 42248 T 75 74483 101862 0.73 9 42248 ^2'^ 75 73908 103764 0.71 8 . 5 257435

1 z ^ y a

7 c 7 0 T 7 Q 1 n 7 4 7- n 74 Q

0 42249 T 75 74483 100552 0.74 9 42249 75 76430 103148 0.74 8.5 360445

Average B 68328 94314 0.725 9.7

Average T 64326 89788 0.71 11.2

B+T Average —

2— 66327 92051 0.72 10.4 501874

Strip Origins

B - Plate bottom; nearest notes, D^-D

T - Plate top; nearest notes, H^-E..
r
Table 11. Tensile Properties of Back Plate Strips

Yield Tens i le

1 SNSR Strength

,

Strength

,

Ratio Elongation

Strip Addition CY.S.) (T.S.) Y.S . in 2 Inches Plate

No

Ml ps i ps i T.S. Percent Mi leage

7637 B 20 70139 87083 0.80 12

7637 T 0

A CI 7 c 16

B+T

2 20 62574 84616 0.74 14 270305

7638 B 25 59310 84897 0.70 13

7638 T 2 5 59932 8 5 6 8 5 0.70 13

/ b J 0 B+T

2 25 59621 85291 0.70 13 312989

7639 B 25 63699 < 90411 0.70 10

7639 T ^ D

/r 1 A n c 6 i y U b 0 6 1 y u

A -70 7 7

/ D J ^ B+T

2 25 62802 88300 0.71 10 732396

7640 B 25 64384 87123 0.74 12

7640 T z o 0 ^ 0 _L 3 n 7 n 1 z

7/ 4 n D fl u B+T

2 25 61816 85719 0.72 12 82182'

7642 B 60 60403 86577 0.70

7642 T 60 63699 93356 0.60 7 A 10

/d4 ^ B+T

2 60 62051 89966 0 .69 10 82183"

7643 B 60 68056 92847 0.73 9 7643 T 60 ^ 1 "7 c r\ 0 "7 -7 A T 0 / / 9 J A "7 1 7 A 1 0

7d4 3 B+T

2 60 65408 90320 0.72 10 283373

7644 B 50 63245 87483 0.72 10

7644 T 50 7 04 Oo A "7 1 /! T 9714 3

A -70 y 7644 B+T

2 50 66286 \j \j ^ \j \j 92313 Q .12 10 258548

7645 B 75 69655 99448 0.70 8

7645 T 75 66552 92414 0.72 10

7645 B+T

2 75 68104 95931 0 .71 9 205811

7646 B 75 71429 100068 0.71 10

7646 T 75 68966 94621 0.73 11

7646 B+T

2 75 70198 97344 0.72 10 468736

Average B 65591 90660 0.72 10

Average T 63204 89296 0.71 11

Overall B+T

Average 2 64398 85478 0.72 10 299614

Adjusted Average 361737

^ Strip Origins

B - Plate bottom; nearest notes, D^-D^.

T - Plate top; nearest notes, K^-E^.

2 Values omitted from adjusted average mileage computation

because of mechanical failure (rigging ball-up)

Table 12. Average Tensile Properties of Selected Face and Back

Plate Strips Versus Plate Mileage

Averaaes

SNSR

Addition

Ml

Specimens

Averaged

No

Hardness

R15T

Yield Tensile

Strength, Strength, Y . S

Elonga-

(Y.S.) (T.S.) T.S. tion

psi psi Ratio Percent Mileage

Face Plate Strips

20 1 89 . 5 59106 86424 0. 685 14 129163

25 4 90 61965 85470 0.726 11.6 512864

65 2 90. 5 65058 92220 0.70 9.8 656036

75 4 91.25 73128 99955 0.73 8.8 506981

Average mileage of all Dlates 451261

Back Plate Strips

20 1 89 62574 84616 0.74 14 270305

25 2 89.5 61212 86796 0.705 11.5 522692^

50 1 90.5 66286 92313 0.72 10 258548

60 1 90 65408 90320 0.72 10 283373^

75 2 91.25 69151 96638 0.715 9.5 337274

Adjusted average mileage of plates 334438

Low mileage

,

81282, of plate No. 7640 due to mechanical failure

was omitted in obtaining ad j us ted average

Low mileage, 81283, of plate No. 7642 due to mechanical failure

was omitted in obtaining adjusted average.

PLATE LEADING EDGE

o o o o o o o o o o o \

PITCH LINE -A

A,

H

4

D

4

H,

PITCH LINE —

o o o o o o o O OOP /

PLATE TRAILING EDGE

gure I. Sketch Showing Individual Note Locations on a Currency

Plate, Plate Alignment on a Printing Press and

Original Positions of Plate Bottom (B) and Top (T) in

Electrof orming Tank,

PLATE LEADING EDGE

ooo o oooo

PITCH LINE

OOO

XJ. >

[ T5-L ' A,

a

C/5 O

M

H

o

a

:^

I—

p -1 r* an

'

I I Mil

L J

1—

=1

I-—< 1 1 ' 1

1 J

}

"l

L„HH »

I

I

I ^

I

iM3l (

—P=ni

B.I I

I

' I ! i I

a

mO

<!

2j irMT!

H r-j-J-J-- 1 D

4| T D - L

,

I i-i 1 4

H n "~ ~ Ji.el— — — —1 D T 6 -2 12 L.-H-i 1 000

PITCH LINE 00000 000

PLATE TRAILING EDGE

Figure 2, Cutting Map Showing Location of Tensile,

Metal lographic and Chemical Analysis

Specimens Cut from Blank Plates, IC

and 2C, Not drawn to scale,

L - Longitudinal tensile specimen,

T - Transverse tensile specimen,

M - Metallographic specimen,

C - Chemical analysis specimen.



•H

-p 1 I rU\ /t( '0 Q) • \ -M fd x:

Q) U)

rn 1 1 1 v< -H m u n^

-M 0) 0

(H

(0 Pi

1—1 ^ fO iH 1 1 iH rd

1-^ 'U CD

O

>-i '0 i-H frt (h , 1 n\ (J m rn frt Ah r )

>-i

H

•r-l ^

(-•

U rn

._J rn 1 •ri u

(11 > frt ij n) ^ H u

(11 r-- >H

U

(-1

r-> >-l

u -M

Lj "5 1 1 H H—

jJOKJ TtT Sh IT( ' u (1) r \ iH rn C\\j

1—

[/3 0 M

•r-\ (X*

C +J fH>H I-M > ijM 0 (1i U P •H o (=; Ah +-' 4J •H ._j

(~i ro r ^ U -P r \ r

n

-J 0) QJ (11 rn Lj CO U n ,

4-i 4-' 1 fd Tr\ UJ o rn ww ro ^ 1 (1 \ 0

td

U

u fll Cn

0) fd

Q

-H • -p •H rH IS e u fd O CN 0 o

+Jo -ri rH CN C 0

-H M-l

X

LOCM

O

in

rH ro o o

iH CM

fd Xi

I
Figure 5. Photomicrographs Showing Structures in Specimens

Cut from Face and Back Plate Strips . The

structures shown ai'e representative of that in

strip cross-sections. Etched with Carapella's

reagent following a 3 acetic to 1 nitric acid

chemical polish. X 250.

Plate

Strip No.

Plate

Type

SNSR Addition,

MlMileage

42239T Face 25 825207

b 42245T Face 75 834963

c 42233T Face 20 129163

d 42248T Face 75 257435

e 7639T Back 25 732396

f . 7646T Back 75 468736

g 7637T Back 20 270305

h 7 64 5T Back 75 205811


o o o

AW

o o o

LEADING EDGE

o o o o o o o — PITCH LINE

A,

IT

-QoQJ L

A.

©

W> (VA /VSA <W\ AAA AAA AAA

PITCH LINE

o o o

^

TRAILING EDGE

Figure 6, Sketch Showing Nature and Approximate

Location of Face Plate Failures.

a o

M M

<^

|jJ H

> O M C(i Q3Q a;w

Q

M

o

Symbols indicate each failure of a simi lar nature

AAAAA - Fatigue cracking.

@ - Dimp le

- - o^- - Ripp lin^I and blisterin

Ball-up (rippling)

LEADING EDGE

ooo o oo o o ooo

../VAA- PITCH LINE

A/VN /WS

O

z

M

H

<O

J

VWVA.

PITCH LINE

OOO o OO oo

TRAILING EDGE

A,

AAA

OOO /

Figure 7. Sketch Showing Nature and Approximate

Location of Back Plate Failures.

Symbols indicate each failure of a similar nature.

/SAAAAA - Fatigue cracking.

Ball-up and rippling, (One Shown;

Approximate location of two

additional failures of this

nature were not reported.)

i NUS 1 HA (HEV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEF.T

1. puhi.ic:ation or rI'Port no. NBSIR 74-425

2, Gov't Accession

No.

3. Recipient's Accession No.

.1. n III: A.\i) SIM ww.K

INVESTIGATION Or /4 L.UKK±iJNCx rJu/iiJi xxi^Lso x-usij PROPERTIES AND PERFORMANCE

5. Publication Date January 1974

6. Performing Organization ( mh

7. Al ' 1 ll()K(S) I. J. Feinberg and T. R. Shives

8. Performing Organ. Report No. NBSIR 74-425

9. I'l KIOKMINC. ()KC,ANI/.A I'lON NAMH AND ADDRHSS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Pron-ct 'Task/Work Unit No. 3120541

11. Co n ir ac t /Cir an t No.

12. Sponsoring Org.iin/..u iuii N.imc- and C^omplete Address (Street, City, State, ZIP)

Electrolytic Section

Bureau of Engraving and Printing

Department of the Treasury

Washington, D. C. 20226

13. Type of Report & Period Covered

Test Report

14. Sponsoring Agency Code

15. SUl'PI.I-MKN l AKY NO I li.S

16. AHS TRAC^T (A 200-word or less (actual summary of most significant information. If document includes a significant

hi bl iography or literature survey, mention it here.) This investigation revealed that a desirable uniformity in

composition, thickness, hardness, microstructure and tensile

properties is attained from plate to plate in electroforming . Tests

programed to determine whether an increase in plate yield and tensile

strengths would afford and improvement in plate service life were

inconclusive due to the scatter in the service lives obtained in the

limited number of tests conducted at various strength levels.

Fatigue cracking, apparently due to excessive vibration and cyclic

stressing, was found to be the chief cause of plate failure in the

tests. It is unlikely that significant improvements in the service

life of G-74 currency plates can be attained until conditions leading

to excessive vibration and cyclic stressing in the G-74 presses are

remedied.

17. KICY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper

iiiiiiie; separated by semicolons

)

Currency plate, electroformed nickel, fatigue, mephanical properties

8. A\ All.AHILn Y [;_ Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGi:,-

[X 1- or Official Distribution. Do Not Release to NTIS

UNCLASSIFIED . 36

1

' Order I'rom Sup. of Doc, U.S. Government Printing Office WashinKton. D.C. 20402. SD Cat. No. CI 3

20. SECURITY CLASS

(THIS PAGE)

22. Price

1 ^ Order l-rom National Technical Information Service (NTIS)

Springfield, Virginia 22151 UNCLASSII-IED

USCOMM.DC 2904<:-l

I

I

!

I

i

!

I

I