UNCLASSIFIED

419851AD._

DEFENSE DOCUMENTATION CENTERFOIl

SCIENTIFIC AND TECHNICAL INFORMATION

CAMERON STATION, ALEXANDRIA, VIRGINIA

UNCLASSIFIED

NOTICE: When government or other drawings, speci-fications or other data are used for any purposeother than in connection with a definitely relatedgovernment procurement operation, the U. S.Government thereby incurs no responsibility, nor anyobligation whatsoever; and the fact that the Govern-ment may have formulated, furnished, or in any waysupplied the said drawings, specifications, or otherdata is not to be regarded by implication or other-wise as in any manner licensing the holder or anyother person or corporation, or conveying any rightsor permission to manufacture, use or sell anypatented invention that may in any way be relatedthereto.

ER-5498

NINTH INTERIM TECHNICAL PROGRESS REPORT

TO

MANUFACTURING TECHNOLOGY DIVISION

AF MATERIALS LABORATORY

tr. AFSC 4ZtERONAUTICAL SYSTEMS DIVISION

TUNGSTEN FORGING

-.,DEVELOPMENT PROGRAM

CONTRACT No. AF 33(600)41629

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19 AUGUST 1963 OIL:

MATERIALS PROCESSING DEPARTMENT

TAPCOA DIVISION OF

T&hmpsom Iamo Wo00dtii&j.I.CLEVEL!AND 17. 01410I

___TAPCO a division ofThompson Ramo Wooldridge Inc.

ASD TR 7-797 (IX) ASD INTERIM REPORT 7-797 (IX)August 1963

TUNGSTEN FORGING DEVELOPMENT PROGRIAM

E. J. Breznyak

Materials Processing DepartmentTAPCO a division of

THOMPSON RAND WOOLDRIDGE INC.Contract-. AF 33(600)-41629

ASD Projectt 7-797

ASD Project Engineert L. C. Polley

Ninth Interim Technical Progress Report19 May 1963 - 19 August 1963

The forging process developed for the Phase V universal thin sectionW-2%Mo forging has been successfully scaled up. Initial forging trialsof the scaled up configuration have been completed with high purity castextruded unalloyed tungsten billets having hot-cold worked and recrystal-lized structures. Test data indicate the superiority of starting billetsof uniformly recrystallized structures. Evaluation of forgings produceddemonstrates that forging quality can be controlled during scale up.Ductile-brittle transition temperature and high temperature tensile pro-perties are reported.

MANUFACTURING TECHNOLOGY DIVISIONAir Force Materials Laboratory

AFSC Aeronautical Systems DivisionUnited States Air Force

Wright-Patterson Air Force Base, Ohio

i

TAPCO a division ofThompson Ramo Wooldrldge Inc

ABSTRACT - SUMMARY ASD TECHNICAL REPOIr 7-797 (IX)August 1963

Ninth Interim Technical Progress Report

TUNGSTEN FORGING DEVELOPMMT PROGRAM

E. J. Breznyak

Materials Processing DepartmentTAPCO a division of

THOMPSON RAM) WOOLDRIDGE INC.

ASD Project Engineer: L. C. Polley

The forging process developed for the Phase V universal thin sectionW-2%Mo forging has been successfully scaled up.

Initial forging trials of the scaled up configuration have been com-pleted. The starting billets were high purity cast-extruded unalloyedtungsten billets having hot-cold worked and recrystallized structures.Analysis of forgeability and property data indicate the superiority ofstarting billets of uniformly recrystallized starting structures. Evalua-tion of unalloyed tungsten thin section forgings produced demonstratesthat superior surface finish, dimensional tolerances, and soundness canbe controlled during scale up.

Ductile-brittle transition temperature and 30000F, 3500°F, 40OO0F,and 5000*F tensile properties of the unalloyed tungsten forgings are re-ported.

ii

J TAPCO a division ofThM.mpsn maem WmIdrdluw Ing

ASD TR 7-797 (IX) ASD INTERIM REPORT 7-797 (IX)August 1963

TUNGSTEN FORGING DEVELOPMENT PROGRAM

E. J. Breznyak

Materials Processing DepartmentTAPCO a division of

THOMPSON RAMD W'OLDRIDGE INC.Contracts AF 33(600)-41629

ASD Project' 7-797

ASD Project Engineer, L. C. Polley

Ninth Interim Technical Progress Report19 May 1963 - 19 August 1963

The forging process developed for the Phase V universal thin sectionW-2%Mo forging has been successfully scaled up. Initial forging trialsof the scaled up configuration have been completed with high purity castextruded unalloyed tungsten billets having hot-cold worked and recrystal-lized structures. Test data indicate the superiority of starting billetsof uniformly recrystallized structures. Evaluation of forgings produceddemonstrates that forging quality can be controlled during scale up.Ductile-brittle transition temperature and high temperature tensile pro-perties are reported.

MANUFACTURING TECHNOLOGY DIVISIONAir Force Materials Laboratory

AFSC Aeronautical Systems DivisionUnited States Air Force

Wright-Patterson Air Force Base, Ohio

iii.

______ TAPCO a division ofThompsOn Namo Woeedridge Inc.

NOTICES

When Government drawings, specifications, or other data are usedfor any purpose other than in connection with a definitely relatedGovernment procurement operation, the United States Government therebyincurs no responsibility nor any obligation whatsoever; and the factthat the Government may have formulated, furnished, or in any waysupplied the said drawings, specifications, or other data, is not tobe regarded by implication or otherwise as in any manner licensing theholder or any other person or corporation, or conveying any rights orpermission to manufacture, use, or sell any patented invention that mayin any way be related thereto.

Copies of ASD Technical Reports should not be returned to the AFSCAeronautical Systems Division unless return is required by security con-siderations, contractual obligations, or notice on a specific document.

iv

_____ TAPCO a division ofThompson Ram@ Woeldwrg Inc.

FORMED

This Interim Technical Progress Report covers the work performedunder Contract AF 33(600)-41629 from 19 May 1963 to 19 August 1963.It is published for technical information only and does not necessarilyrepresent the recommendations, conclusions, or approval of the Air Force.

This contract with the Materials Technology of TAPCO a division ofThompson Rmno Wooldridge Inc., Cleveland, Ohio was initiated under ASDProject 7-797, "Tungsten Forging Development". It is administered underthe direction of Mr. L. C. Polley of the Manufacturing Technology Division,Air Force Materials Laboratory, AFSC Aeronautical Systems Division, Wright-Patterson Air Force Base, Ohio.

E. J. Breznyak of the Materials Processing Department, TAPCO adivision of Thompson Ramo Wooldridge was the Engineer in charge.

PUBLICATION REVIEW

Approved byt fC. R. CookSenior Development Metallurgist

Approved byt // -ý AA. S. NenyManager,, Materials ocessing

v

/• ____TAPCO a division ofThRmpwM Remn Wcldridge Inc.

TABLE OF CONTENTS

Page Nos.

I INTRODUCTION . . . . . . . . . . . . . . . . . . . o 1

II PHASE VI PROGRAM. e * ... . . .o. . . . . . .0 . . . . • 3

III FORGING BILLET PROCUREMENT . . . . . . . . . ..... .... 5

IV DEVELOPMENT OF SCALED UP THIN SECTION FORGING . . . . . . 6

A. Component, Sequence, and Tooling Design . . . . . . . 6B. Heating and Forging Equipment • • ......... . 6C. Forging Development • • • • • • • • • • • • .. . . 11

1. Sequence Metal Flow Evaluation .......... 112. Tungsten Forging Trials ............. 11

a) Recrystallized Starting Billet Stock . . . . . 14b) Hot-Cold Worked Starting Billet Stock .o. . 14

V FORGING EVALUATION . ................... 21

A. Yield &.. ... . .. . . . ... . . . .. . . ...0 0 0 0 0 22

B. Dimensions . .o. .o o .. ... . . . . . . . . .0 . 22C. Surface Finish . o o .. o . .. * .. . . . . .. .. . 22D. Non-Destructive Testing ....... ........ 22E. Microstructure o . . . . . • • 0 * 0 0 . 0 . .. . • • 26F. Recrystallization . . ........ ...... . . 26G. Mechanical Properties .a. .* . * .. . . . . . . . . . 31

l. Ductile-Brittle Transition Temperature . . . . . . 31

2. High Temperature Tensile Properties .. .. • . . 31

H. Analysis of Forging Tooling o • .o. • ...... • 36

VI CONCLUSIONS o . . . . . . . . . . . . . . . . . . . . . 38

VII REFERENCES .. ... . . . . . . .o . . . .o * & o . . . . 39

VIII PROGRAM FOR NEXT PERIOD . o .. . . . . . . o . o . . . 40

IX DISTRIBUTION LIST .. ... . . . . . . . . . o . . . . 41

vi

TAPCO a division ofWThompson RMem Wwdridge Inc.

I INTRODUCTION

The use of tungsten for ultrahigh temperature components in aerospacevehicles is still a relatively new concept. Only since projected operatingtemperatures have reached 3000F and above has the density of tungsten beenviewed as anything but undesirable. The success of rocket nozzle engineersin designing around tungsten's density has further prompted a re-evaluationof the applicability of tungsten as a material for load carrying structuralcomponents.

The basic manufacturing method for aerospace structural components isforging. For tungsten, however, forging methods did not exist except asrelated to conversion steps in the lamp industry and as used for preliminaryrocket nozzle shaping. For this reason the Aeronautical Systems Division,Manufacturing Technology Laboratory. initiated the present program withThompson Ramo Wooldridge for the development of forging methods for tung-sten and its alloys.

The principal objective of the program was the development of methodsfor producing tungsten forgings for structural use in aerospace vehicles.To accomplish this aim the program was originally divided into five phasesconsistent with the state-of-the-art and with the non-integrated nature ofthe refractory metal and forging industries. The objectives of each ofthese original five phases are summarized belowt

Phase I State-of-the-Art-Analysis

An evaluation of the tungsten and forging industry state-of-the-art in order to satisfactorily plan the program for subsequent phases.This was completed and reported in the First Interim Technical ProgressReport on 31 August 1960.

Phase II Billet Process Development

The development of processes for the production and conversionof sound tungsten ingots to quality forging bar stock. This was completedand reported in the Second Interim Technical Progress Report on 12 December1960.

Phase III Development of the Forging Operation

The forging of tungsten billets to establish forging processparameters, controls, and tests for the controlled forging of tungsten.This was completed and reported in the Third and Fourth Interim TechnicalProgress Reports on 27 March and 27 May 1961 respectively.

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A TAPCO a division of"PLRWI Thompson Ramo Wooldridge Inc.

Phase IV Forging Process Verification and Post-Forging Development

Forging tungsten to verify the developed process and the sub-sequent development of applicable post-forging operations. This wascompleted and reported in the Fifth Interim Technical Progress Reporton 9 November 1961.

Phase V Final Pilot Production

Pilot production to demonstrate reliability of the developedprocess and of the forgings produced. This phase was successfully com-pleted with Phase IV and also reported in the Fifth Interim TechnicalProgress Report.

That all of the program objectives were met is well documented(1-5). In addition, the original objectives of Phases III, IV, and V;i.e., those of development and pilot production verification of controlledprecision forging methods for structural tungsten components, were ac-complished within the boundaries of the third and the fourth phases. Forthese reasons the program has been modified and extended for adaptationof the developed technique to the continuing and more immediate problemof thin section, nonstructural tungsten shapes currently required by therocket engine industry. The specific objectives of the revised fifthphase and the additional sixth phase ares

Phase V Development of Thin Section Forging Process

Extension of the developed forging process to controlled pre-cision forging of thin section, nonstructural tungsten shapes havingoptimum properties.

Phase VI Verification of Thin Section Forging Process

Production of scaled-up thin section forgings to verify anddemonstrate applicability of the process.

This Ninth Interim Technical Progress Report details theinitial scaled-up forging trials of the Phase VI program effort.

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TAPCO o division ofThompson Ramo Wooldridge Inc.

II PHASE VI PROGRAM

The objective of Phase V was adaptation of the process developed forstructural forgings to thin section tungsten components presently requiredfor aerospace applications. That the objective has been successfullyachieved has been demonstrated( 6 9 7), i.e., the evaluation of the closetolerance forging sequence developed showed dimensional reproducibility,excellent as-forged surfaces, and desireable grain flow orientation inthe final thin section components. The Phase VI objective is to verifythis thin section tungsten forging process, developed during Phase V, byscaling up to a larger specific thin section design. The principalcriterion to be used for judging the universal applicability of theforging process is the extent to which the mechanical properties of thethin section forging can be controlled and maintained during scale-up.The tasks scheduled for accomplishing the Phase VI objectives ares

1. Design of a scaled-up configuration and tooling sequence com-patible with both previous design and process data and the re-quirements of the aerospace industry for thin section tungstencomponents in the 50 to 70 pound range.

2. Selection and procurement of arc melted and extruded forgingbillets.

3. Development of the scaled-up forging process to provide optimumproperties in the thin section component.

4. Property determination and evaluation of the scaled-up thinsection tungsten component.

The organization of these interrelated tasks into the Phase VI pro-gram effort is illustrated schematically in Figure L.

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III FORGING BILLET PROCUREMENT

Four cast-extruded unalloyed tungsten billets were procured fromClimax Molybdenum of Michigan for the initial Phase VI forging trials.The billets were conditioned from 8 in. diameter arc-cast ingots ex-truded at a reduction ratio of 3.5/1 within a temperature range of3100-3150*F. Two forging billets with as-extruded and stress relievedhot-cold worked structures and two with fully recrystallized structureswere selected for the initial forging effort. The selection of thesestarting structures was based upon results of upset forgeability testsand microstructure examinations of the extrusions from which it wasconcluded thatt

1. Upsetting of stress relieved slugs resulted in a non-uniformlyworked structure in comparison to the recrystallized and upsetextrusion.

2. The grain size of the hot-cold worked grains was at least oneorder of magnitude larger than the recrystallized grains.

The billets ground at TAPCO to the designated forging billet sizeof 3.750 in. diameter by 6.500 in. length met the requirements of thebillet quality control specification reported previously( 8 ). Prior toforging, the four billets were identified according to starting structureand their position within the extrusion, i.e., R-1 and R-2 refer torecrystallized billets sectioned from first and second positions start-ing from the lead end of the extrusion while S-2 and S-3 designate stressrelieved billets etc.

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/I TAPCO a division of

Thompson Romo Wooldridge Inc.

IV DEVELOPMENT OF SCALED UP THIN SECTION DESIGN

A. Component, Sequence, and Tooling Design

The scaled up thin section configuration and the six stage sequencedesigned to produce the forging are shown in Figures 2 and 3. The forg-ings produced at each stage of the sequence are displayed in Figure 4.

The closed die sequence established the forging volume to fill eachstage of the sequence at 72 in0 3:,(3 3/4 in. diameter by 6.1/3 in. long)as compared to the Phase V billet volume of 28.7 in°3. (2-3/4 in. diameterby 4-7/8 in. long).

Because of the severe 70% upset requirement (see Figure 3) of thescaled up sequence, a third closed die upsetting operation was added tothe forging sequence developed during Phase V. The die utilized for thethird upsetting operation was the same die used during the subsequentthree back extrusion operations.

During the Phase V back extrusion operations, moderate surfacetearing in the regions of the inner and outer cup radii were observed(7),In an attempt to alleviate this surface tearing, larger radii on punchand die faces were incorporated into the scaled up design.

B. Heating and Forging Equipment

An electric furnace purged with argon was used for heating. Tem-perature measurements were made using an optical pyrometer shown to bewithin ±20F of duplicate Chromel-Alumel thermocouple readings for theforging temperature range utilized (2200OF to 23500F) A total billetheating time of 30 minutes, as previously established(7), was used toreach forging temperatures. After the forging blow was struck at thepredetermined forging temperature, the tungsten work pieces were re-turned for a 30 minute period to a second electric furnace at 2000OFfor a temperature equalization. The work pieces were then buried insilocel allowing the forged configuration to uniformly slow cool from2000°F through the ductile-brittle transition temperature.

Component size and pressure requirements necessitated the use ofthe 8000 ton mechanical crank press. The press utilizes a 20 in. strokeand is equipped with a vertical tooling adjustment with capability formaintaining a tolerance of +-0.003. The 8000 ton press and the heatingfacility used during the Phase VI forging trials are shown in Figure 5.

-6

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Forging Configurations Produced through Six Step ForgingSequence as Shown by Steel Set-Up Billets and OriddedSteel Composite Billets

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C. Forging Developmnt

1. Sequence Metal Flow Evaluation

To aid in metal flow evaluation of the tooling sequence de-signed, three composite gridded steel billets were assembled, as pre-viously detailed((), and forged at 1800"F. The billets were witheld asforged to the upset No. 3, semin-coin, and coin configurations as shownin Figure 6. These forgings were then sectioned and etched to show themode of metal redistribution produced by the designed sequence, as shownin Figure 7. The severity of the sidewall metal movement during thQcoining blow is apparent. A review of the Phase V gridded sections,'7)reveals the similarities produced in the scaled up section, i.e.:

a. The sidewall metal flow, although more severe, is uni-form with flow lines parallel to the punch and sidewall.

b. The cup bottom is formed by the center billet core whilethe cup sidewalls are formed by the elongated outercylinders.

c. Lapping or tearing tendencies of the work piece are notapparent at the tooling radii contact surfaces.

2. Tungsten Forging Trials

Four cast-extruded unalloyed tungsten forging billets, two ofas-extruded and stress relieved hot-cold worked structures (Nos. S-2 andS-3) and two in a fully recrystallized condition (Nos. R-1 and R-2) com-prised the starting stock for the tungsten forging trials. Low carbonsteel stock machined to the starting billet size and the gridded compositesteel billets provided the setup billets for preliminary tooling adjustments.

The punch and die inserts were preheated to a temperature rangeof approximately 350"F to 425"F. A thin coating of colloidal graphitelubricant was applied to the tooling surfaces prior to each blow. Thetungsten billets were forged bare; the volatile surface oxide producedduring heating provides lubrication. The optimum forging temperaturesestablished during Phase V prompted the selection of the following tem-peratures for the scaled up six stage sequencet

Upset No. 1 2350OF

Upset No. 2 23009FUpset No. 3 2300"F

Blockdown 2250OFSemi-Coin 2200OF

Coin 2200OF

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IV

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The tungsten billets were forged as outlined in Section IV-B.The forging data are listed in Table I. Post forging processing uponcompletion of each forging blow consisted of sand blasting followed bysuperzyglo fluorescent penetrant inspection of the forged surface. Sur-face irregularities were noted (see Table I), repaired manually with anair grinder, and re-examined by red dye penetrant inspection. A summaryof the observations is as followss

a. Recrystallized Starting Billet Stock

Billet Nos. R-1 and R-2 generally forged well throughoutthe sequence. Some sidewall roughness was exhibited after Upset No. 1.This surface irregularity, attributed to the unsupported lateral movementof the billet sidewall during the initial 38% upset, was readily repairedby grinding. During the subsequent forging stages, the surface appearanceof the tungsten pieces progressively improved. The only surface condition-ing required during the back extrusion operations was slight blending ofsurface tears in the inner and outer cup radii. The as-coined forged andsand blasted surface appearance of Nos. R-1 and R-2 are compared to Nos.S-2 and 8-3 in Figures 8 and 9.

b. Hot-Cold Worked Billet Stock

The degree of in-process repairing required after each ofthe first four stages for billets S-2 and S-3 are noted in Table I. Bil-let S-2 cracked severely in the die flat and radius surface region duringupset No. 2 (see Figure 8). The deep cracking was non-repairable andtherefore No. S-2 was used as the tungsten set up billet for the sub-sequent forging stages. Since forging process parameters were constant,the rough surfaces, surface tears, and radial cracking observed for bil-lets S-2 and S-3 through the first four stages can be, in part, relatedto non-uniform response to the forging deformation of the mixed grainsizes known to exist in the initial forging billets. The sidewall sur-face condition of Nos. S-2 and S-3 greatly improved during the semi-coinand coin operations, where complete work piece support was provided bythe punch and die contours throughout the forging stroke. However, acomparison of the surface appearance, particularly in the outer cupradius and bottom surface of forgings S-3 and R-1 (Figure 9) show thesurface superiority of the latter. Forging S-3, although requiringextensive conditioning between operations, resulted in a sound coinedforging.

Coined forgings R-2 and S-2 were sectioned to evaluatethe metal flow produced by the sequence and the effect of the startingmicrostructure on the final forged part. Center section macrostructuresof these coined pieces are shown in Figures 10 and 11. A close comparisonof these tungsten sections reveals no apparent differences in the macro

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____ TAPCO a division ofThompson aemo WIldridge Inc.

TABLE I

PHASE VI TUNGSTEN FORGING TRIALS

Upset No. 1

UpsetBillet Forging(l' Tooling Temp. OF Height

No. Temp. *F Punch Die In. Condition of Forging

R-1(2) 2360 350 350 4.250 Top and bottom face smooth,slight tear near flash area,rough sidewall.

R-2 2370 400 400 4.248 Rough sidewall.

S-2 2370 350 370 4.260 Crack 1/4" on die side flat,sidewall very rough.

S-3 2380 340 400 4.265 Crack on sidewall 3/8" longby approximately 1/8" deep,very rough sidewall.

Upset No. 2

R-1(2) 2320 400 400 3.060 Good surface appearance, side-wall needed only slight buffingtouch up.

R-2 2320 380 350 3.062 Good surface appearance, side-wall needed only slight buffingtouch up.

S-2 2330 390 400 3.071 Repaired area opened into aseries of very severe cracks(non-repairable).

S-3 2330 380 370 3.070 Rough sidewall, surface tearingon flash flat face area.

Upset No.3

R-1 2310 420 380 2-1/4 Good appearance all over.

R-2 2320 350 370 2-1/4 Good appearanice all over.

S-2(2) 2300 400 400 2-1/4 Rough sidewall, cracks on dieface not propagating.

S-3 2320 370 400 2-1/4 Rough sidewall, slight crackin previously repaired area,repairable.

Blockdown

R-I 2260 410 380 1.460 Good sidewall surface, neededblending in I.D. and O.D.radius.

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_TAPCO a division ofThemps. Raemo We.ldridg. Inc.

TABLE I (continued)

Upset

Billet Forging(') Tooling Temp. OF HeightNo. Tem. OF Punch Die In. Condition of Forging

Blockdown (continued)

R-2 2250 380 370 1.450 Good sidewall surface, neededblending in I.D. and O.D.radius.

S-2(2) 2260 380 390 1.459 Required I.D. and O.D. Blend-ing, cracks not propagating.

S-3 2260 0oo ho0 1.456 Good surface like R-1 and R-2,slight radial crack on 0.D.radius about I/" long.

Semi-Coin

R-1 2185 350 360 1.010 Surface condition excellent,only slightly rough areas inO.D. radius.

R-2 2220 370 370 1.050 Surface condition excellent,only slightly rough areas in0.D. radius.

S-2(2) 2205 350 400 1.065 Surface condition excellent,except for moderate surfacetears in 0.D radius.

S-3 2220 360 400 1.055 Surface condition excellent,except for moderate surfacetears in O.D. radius.

Coin

R-1 2220 380 400 .325 See Figures 8 and 9.

R-2 2210 380 410 .335 See Figure 8.

S-2(2) 2205 370 380 .338 See Figures 8 and 9.

S-3 2220 380 400 .336 See Figure 8.

(1) Optical temperature determinations (see Section IV-B).

(2) Used as tungsten set-up piece.

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flow patterns; both sections appear to be fully wrought in spite of dis-similar starting structures. A further comparison of the tungsten sectionsto the coined composite steel section emphasizes the metal flow similarities,is., the elongated flow patterns reflect the severity of the work empartedduring the back extrusion operations. Analysis of the forging trials andthe appearance of the resultant macrostructures produced by the six stagesequence verified the original sequence design concept during scale up.No tooling modifications are required for the remaining forging operations.

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/TRW TAPCO a division of

Thompson Ramo Wooldridge Inc

V FORGING EVALUATION

A. Yield

The starting weight for the unalloyed tungsten billets was a nominal50 pounds as compared to an average coined forging weight of 48.1 pounds.As with the reported Phase V forging(7) the resultant 96.2% forging yieldis high. Since the Phase VI sequence retains the original Phase V designconcept during scale up. the forging metal losses are similarly incurredsolely by in-process surface conditioning and oxidation. Flash patternscrap was essentially eliminated by the tooling design.

B. Dimensions

The coined forg-ngs were dimensioned at the locations "A"9, "B"u, and"C" shown in Figure 2. Position "AP' thickness was located at a height of4-1/4 in. from the cup bottom and was checked at four 900 rotated positions.The dimensions of the six positions checked are recorded in Table II. Thedata show the dimensiona.l reproducibility achieved. The cup bottom dia-meter dimensions are within 0.006 irn the greatest deviation from nominaldesign dimension being 0.008 in. The web sections were reduced below the0.375 in. design dimension by approximately 0.040 in. and were within 0.013in. The cup sidewall thicknesses were well within the maximum 0.445 in.dimension targeted for this position. The greatest variation for the *A*dimension was found to be 0.024 in.

To aid in determination of a forging envelope for this part, coinedforging S&3 was selected at random, and prepared for concentricity measure-ments(7). The measurements were recorded for five I.D. and O.D. heightpositions at four 900 rotations, as shown in Figure 12. The data arelisted in Table III. The outer sidewall concentricity varied by a maximumof 0.006 in. while the greatest inner sidewall concentricity variationswere 0.022 in. Based on these results and subsequent surface finishmeasurements, an adequate forging envelope would consist of approximately0.010 in. and 0.030 in. on the outer and inner forging walls respectively.The Phase VI forgings showed an 0.008 in. improvement in inner sidewallconcentricity as compared to Phase V forgings.

C. Surface Finish

Figures 8 and 9 illustrate the superior forged surface appearanceobtained during Phase VI. 6idewail surface roughness measurements forthese forgings ranged from 40 to 60 RMS as was reported(7) for Phase Vforgings using identical lubrication practice.

D. Non-Destructive Testing

Super zyglo fluorescent penetrant inspection revealed no additionalsurface discontinuities other than those described in Section IV-C, Figures8 and 9. The surface discontinuities found in the coined forgings consisted

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solely of tears in the outer surface cup bottom and radius of forgings8-2 and S-3.

Ultrasonic testing could not be adequately ad~pted to the inspectionof the thin walled inserts as previously discussed'd-). The applicationof eddy current testing of the tugsten forgings was investigated. Theeffective test penetration of the tungsten sidewall using a Magna Testunit, Model No. FM 110, was found to be approximately 0.050 in. Theobvious limitation of this technique precluded its applicability.

E. Microstructure

To determine the effect of the initial starting billet structureand the forging process on the tungsten work piece microstructure, forg-ings R-2 and S-2 were sectioned and prepared for metallographic examina-tion. The as-forged microstructures and corresponding DPH hardness valuesof these sections are shown in Figures 13 and 4.,

Slightly higher hardness values were recorded for forging S-2.However, both forgings exhibited more uniform hardness values throughoutthe section than reported for the Phase V forgings(7). Although no ap-parent macrostructure differences for forgings R-2 and S-2 could be noted(see Section IV-C), examination of the microstructures clearly indicatedthe structure desireability of forging R-2. The "R" designated billetsforged to the coin configuration showedi

1. Considerably finer grain size;

2. Greater structure uniformity; and

3. M-re uniformly worked structures.

F. Recrystallization

Forgings R-2 and S-2 were further sectioned to provide additionalsamples to investigate the response of the cold-worked structures tothermal treatment. The recrystallization process was followed in theforging area corresponding to the critical throat section of nozzleinserts. Forging sections were given one hour isochronal heat treat-ments over the temperature range of 2300OF to 2700 0 F. The microstructuresand hardness data are shown in Figures 15 and 16.

Initiation of the one hour recrystallization in the heavily workedsection adjacent to the punch (I.D. throat) was seen to occur as low as23000F. The start of recrystallization for the 0.D. section occurred atapproximately 24000F. The one hour recrystallization temperature of No.R-2 occurred at 2500*F while No. S-2 was found to be completely recrystal-lized at 26000F. The higher recrystallization temperature of forging S-2can be associated with the coarser grained areas observed in the micro-

- 26 -

_________________________________________TAPCO a division ofThompson Remo Wooldridge Inc.

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structure. That the start of recrystallization of the Phase VI unalloyedtungsten forgings was observed to occur at approximately 400OF lower thanfor reported Phase V W-2%MO forgings(7) can be attributed in part to thefollowingi

1. Finer initial billet grain size;

2. S3vere deformation imparted the work piece; and

3. Low reported interstitial levels,

G. Mechanical Properties

Blanks were sectioned from forgings R-2 and S-2, as illustrated inFigure 17, to provide specimens for the determination of mechanical pro-perties. Ductile-brittle transition temperature and elevated temperaturetensile properties were determined. The specimen configurations utilizedfor the testing effort were as previously reported(7).

1. Ductile-Brittle Transition Temperature

The specimen blanks machined from forgings R-2 and S-2 werecentrally positioned within the forging sidewall (Figure 17) to provideproperties representative of the worst detectable condition in the forg-ing sidewall. The effect of specimen position in the forging sidewallhas been discussed(7). The tensile ductile-brittle transition testingwas accomplished on an Instron tensile tester using a constant crossheadspeec of 0.020 in./min.

The results of the tensile tests are tabulated in Table IV.Reduction of area and elongation values are plotted for the two forgingsin Figure 18. The tensile data indicate the transition temperature ofthe center section of the sidewall to be 300OF and 325"F for forgingsR-2 and S-2 respectively. These ductile-brittle transition temperaturevalues are approximately 1000F lower than reported for the Phase Vforgings(7). More significantly, specimen ductility was observed asnoted in Table IV at the lowest test temperature (15O0F).

2. High Temperature Properties

Test specimens were machined from sidewall blanks of for~ingsR-2 and S-2. Testing procedures for the radiant heated specimens at3000OF and 4000OF and the self resistance heated specimens at 5000Fhave been outlined(4,7). The results of testing are summarized inTable V.

The strength levels observed over the temperature range tested(3000"F to 5000"F) for the two cast-extruded unalloyed tungsten forgingsare comparable to data reported in the Phase I State-of-the-Art Survey

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/R___ TAPCO a division ofT/•mpD Raemo W.Wridge Inc-.

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Location of Test Specimens Taken from Forging Sidewall

- 32 - Figure 17

__ __ __ _ __ __ __ _ TAPCO a division ofTh.aw.paea MamRome WOMIId Inc.

TABLE IV

TENSILE TEST DATA FOR PHASE VI THIN SECTION FORGINGS*

TestTemp. 0.2% Y.S. U.T.S. %

"F (psi) (psi) % R.A. Elongation

Coin Forging No. (S-2)

150 180,300 180,300 1.3 1.3200 167,500 167,700 2.5 3.1250 146,ooo 146,000 6.3 2.8300 146,300 147,300 16.2 7.2

350 136,700 137,500 13.2 10.0400 119,300 119,300 30.4 17.9

Coin Forging No. (R-2)

150- 173,900 175,000 1.0 0.9200 163,800 16 6,4W0 1,9 1.4

250 149,100 152,000 1.2 1.2

300 141,o00 144.,400 5.1 10.5350 130,000 132,900 36.8 19.4450 110,200 114,600 50.5 21.7

* Tests were conducted using a constant crosshead speed of .020/mmin.

Notes Specimens were tested in the as-forged condition. Specimens weremachined from forging sidewall blanks as shown in Figure 17.

- 33 -

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TEST TEMPERATURE (OF).

Tensile Ductile-Brittle Transition Properties ofCoined Tungsten Forging Nos. R-2 and S-2

- - Figure 18

/____•_ TAPCO a division ofTlhmmp" name Weel*r Ic..

TABLE V

HIGH TEMPERATURE TENSILE PROPERTIES OF PHASE VITHIN SECTION TUNGSTEN FORGINGS*

TestTemp. 0.2% Y.S. U.T.S. %

OF (psi) (psi) % R. A. Elongation

Coin Forging No. (S-2)

5ooo 3,400 5,0OO - -

4000 44,000 7,200 98 100.6

3500 5,500 10,4OO 98 64.2

3000 8,400 15,,8oo 98 69.0

Coin Forging No. (R-2)

5ooo 4,200 14,8OO - -

4OOO 3,400 6,4Oo 98 67.6

3500 6,000 11,500 96 77.8

3000 7,300 16,200 85.5 66.0

* Tests were conducted using a constant crosshead speed of .0200/min.

Notes Specimens were tested in the as-forged condition. Specimens weremachined from forging sidewall blanks as shown in Figure 17.

- 35 -

A TAPCO a diilou ofT/h.m.pn Rem Woridge IM

for extruded and swaged arc cast unalloyed tungsten('). A comparison ofthe high temperature tensile properties of previously tested W-Mo alloysto the unalloyed tungsten forgings shows sig ificantly higher strengthsprevail for the W-Mo alloys below 4000o-G, 7). At 4000OF comparablestrength levels are observed. Above 4009OF the solid solution strengthen-ing effect of molybdenum is lost and the unalloyed tungsten exhibitsgreater tensile strengths.

H. Analysis of Forging Tooling

The punch and die inserts used during Phase VI are shown in Figure19. The tooling was machined from AISI type H-12 tool steel and hardenedto Re 5 0-52. Rapid billet transfers enabled the use of conventional tool-ing materials and tooling lubricants in spite of forging temperatures of2 3 50"F. A post forging visual inspection of the tooline as well as thedimensional consistency of the coined forgings indicated no perceptabletooling wear. Since only four forgings were produced, estimates of tool-ing life are currently precluded.

- 36 -

__TAPCO a division of/TW "Thompson Remo Wooldridge Inc.

(A) Usetting Punches

(B) Back Extrusion lunches

(C) Dies S .1

Punch and Die Inserts Used During Forging Trials

- 37 - Figure 1930"

STAPCO a division ofThompson Memo Wboildrfd I#A

VI CONCLUSIONS

The forging process developed for the Phase V universal thin sectionforging has been successfully scaled up. The following conclusions canbe drawn from the forgeability and property evaluations of the scaled uptungsten configurations

1. The in-process controls developed and forging parametersestablished during Phase V have been verified as adequateto control the scaled up Phase VI tungsten forging process.The results shows

a. Excellent as forged surfaces,

b. The optimum forging temperature range developed forfhase V (2350OF to 2200°F) is applicable to the scaledup forging, and

c. Dimenqional consistency can be controlled during scaleup.

2. Unalloyed tungsten of fine grained fully recrystallized structuresas compared to billets of initially hot-cold worked structureshas been shown the former to possess:

a. Bstter forgeability, and

b. More uniform as forged microstructures.

3. Low ductile-brittle transition temperatures observed for thecoined tungsten forgings verify the original design conceptfor production of thin wall insert configurations and furtheremphasize the severity of the deformation emparted by theforging process.

- 38 -

_TAPCO a division ofThompson Rama W.tdrWg. Inc.

VII REFERENCES

1. "Tungsten Forging Development Program", First Interim TechnicalProgress Report, Contract AF 33(600)-41629, August 1960, MaterialsProcessing Department, Thompson Rand Wooldridge Inc.

2. "Tungsten Forging Development Program", Second Interim TechnicalProgress Report, Contract AF 33( 600)-416 29, December 1960, MaterialsProcessing Department, Thompson Ramo Wooldridge Inc.

3. "Tungsten Forging Development Program", Third Interim TechnicalProgress Report, Contract AF 33(600)-41629, March 1961, F. N. Lakeand E. J. Breznyak, Thompson Ramo Wooldridge Inc.

4. *Tungsten Forging Development Program", Fourth Interim TechnicalProgress Report, Contract AF 33(600)-41629, May 1961, F. N. lake,E. J. Breznyak, and G. S. Doble, Thompson Ramo Wooldridge Inc.

5. "Tungsten Forging Development Program", Fifth Interim TechnicalProgress Report, Contract AF 33(600)-41629, November 1961, F. N.Lake, Thompson Ramo Wooldridge Inc.

6. "Tungsten Forging Development Program", Sixth Interim TechnicalProgress Report, Contract AF 33(600)-41629, September 1962, F. N.Lake, Thompson Ramo Wooldridge Inc.

7. "Tungsten Forging Development Program", Seventh Interim TechnicalProgress Report, Contract AF 33(600)-41629, November 30, 1962,E. J. Breznyak and F. N. Lake, Thompson Ramo Wooldridge Inc.

8. "Tungsten Forging Development Program", Eighth Interim TechnicalProgress Report, Contract AF 33(600)-41629, May 19, 1963, E. J.Breznyak, Thompson Ramo Wooldridge Inc.

- 39 -

/TRW TAPCO a divis°on ofThompson RADMO W0..Idrd ION

VIII PROGRAM FOR THE NEXT PERIOD

Duxring the next reporting period the Phase VI program will be com-pleted. This will includet

1. Procurement of eight additional cast-extruded tungsten billetswith a fully recrystallized microstructure.

2. Forging of the eight tungsten billets.

3. Forging and property evaluation of the parts produced todemonstrate the reproducibility of the process.

- 40 -

TAPCO a division ofThompson Ramo WooldrId" Ina.

IX DISTRIBUTION LIST

ASD (ASRCTB) Armour Research FoundationWright-Patterson AFB, Ohio (4) Metals Research Department

10 West 35th StreetASD (ASRC, Dr. A. M. Lovelace) Chicago 16, IllinoisWright-Patterson AFB, Ohio

ASTIAASD (ASRCE, Mr. J. Teres) Arlington Hall StationWright-Patterson AFB, Ohio Arlington 12, Virginia (4)

ASD (ASRCM), Mr. W. C. Ramke) Atomic Products DivisionWright-Patterson AFB. Ohio General Electric Company

Attention: Mr. M. S. Sanderson

ASD (ASRCMP-4, Mr. S. Inouye) P. 0. Box 846Wright-Patterson AFB, Ohio Pleasanton, California

ASD (ASRCEM-IA, Mrs. N. Ragen) Babcock & Wilcox CompanyWright-Patterson AFBq Ohio (2) Attention: Chief Metallurgist

Beaver Falls, PennsylvaniaAerojet-General CorporationAttention: Dr. A. Levy Baldwin-Lima-HamiltonP. 0. Box 1947 Attentiont Mr. George LessisSacramento, California i1 5th Avenue

New York 3, New YorkAerospace Industries Association610 Shoreham Building 6539 Test GroupWashington 5, D. C. Attention: DGSCH

Edwards AFB, CaliforniaAllegheny Ludlum Steel CorporationAttentions Mr. Robb Hente Battelle Memorial InstituteBrackenridge, Pennsylvania Defense Metals Information Center

505 King AvenueAlloyd Research Corporation Columbus 1i OhioAttentions Mr. Louis MagerGeneral Manager Bell Aeropsace Corporation202 Arsenal Street Attention: Manager, Production Ekg.Watertown 72, Massachusetts Box 482

Fort Worth 1, TexasArcturus Manufacturing CorporationAttentions Chief Engineer Bell Aerosystems Company4301 Lincoln Boulevard Attention: Manager, Production Eng.Venice, California Buffalo 5, New York

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Bendix Products Division Crucible Steel Company of AmericaBendix Aviation Corporation Central Research LaboratoryAttention% Chief Engineer 234 Atwood Street401 N. Bendix Drive Pittsburgh 13, PennsylvaniaSouth Bend, Indiana

Curtis s-Wright CorporationThe Boeing Company Attention: Manager, MetallurgyMaterials Mechanical & Structures Branch Wood Ridge, New JerseySystems Management OfficeP. 0. Box 3707 Douglas Aircraft Company, Inc.Seattle 24, Washington 827 Lapham Street

El Segundo, CaliforniaCameron Iron WorksAttentions Mr. J. W. Brougher Douglas Aircraft Company, Inc.Vice President and Manager Attentions Plant Eng. SupervisorSpecial Products Division 3855 Lakewood BoulevardP. 0. Box 1212 Long Beach 8, CaliforniaHouston 1, Texas

Douglas Aircraft Company, Inc.Canton Drop Forging & Manufacturing Co. Attention: Works ManagerAttentions Quality Control Manager 3000 Ocean Park Boulevard2100 Wilett Avenue Santa Monica, CaliforniaCanton 2, Ohio

Douglas Aircraft Company, Inc.Chance Vought Corporation Production Design EngineeringVought Aeronautics Division 2000 N. Memorial DriveAttention: Chief Librarian Tulsa, OklahomaP. 0. Box 5907Dallas, Texas E. I. du Pont de Nemours & Co., Inc.

Attention: Mr. E. M. MahlaClimax Molybdenum Co. of Michigan Experimental StationAttention: Mr. G. A. Timmons Wilmington 98, Delaware

Vice President14410 Woodrow Wilson Fansteel Metallurgical Company

Detroit 38, Michigan Attention: ChiefMetallurgical Division

Commander 2200 N. Sheridan RoadArmy Ballistic Missile Agency North Chicago, IllinoisResearch LaboratoryRedstone Arsenal, Alabama Fansteel Metallurgical Company

Attention: Director of ResearchCrucible Steel Company of America North Chicago, IllinoisMidland Research LaboratoryP. 0. Box 226 Firth Sterling, Inc.Midland, Pennsylvania Attention: Chief Metallurgist

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Frankfort Arsenal Kelsey Hayes CompanyPhiladelphia 37, Pensylvania Attention: Director of Research

Metals Division

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5481 Packard AvenueGeneral Dynamics Corporation/Astronautics Cudahy, WisconsinAttention: Mr. A. Hurlich, SupervisorMaterials Research Group Lockheed Aircraft Corp.Mail Zone 595-20, P. 0. Box 1128 Missile Systems DivisionSan Diego 12, California Palo Alto, California

General Electric Company Lockheed Aircraft Corp.Alloy Studies Unit Missile Systems DivisionAttention: Mr. E. S. Jones, Manager Sunnyvale, CaliforniaMetallurgical Engineering-AROBuilding 200, FPID Lockheed Aircraft Corp.Cincinnati 15, Ohio California Division

Attention: Director of Eng.General Electric Company P. 0. Box 511Cleveland Wire Plant Burbank, CaliforniaAttention: Chief Metallurgist21800 Tungsten Road Lycoming DivisionCleveland, Ohio AVCO Manufacturing Corp.

Attention: Manufacturing Eng.Hercules Powder Company Stratford, ConnecticutAttention: Mr. D. E. Borgmeier

Head, Nozzle Design Group The Marquardt CorporationBeehive Bank Building Attention: Mr. Gene KleinSalt Lake City, Utah Manufacturing Engineer

P. 0. Box 670Grumman Aircraft Engineering Corp. Ogden, UtahAttention: Mfg. Research CoordinatorPlant 12 The Marquardt CorporationBethpage, Long Island, New York Attention: Metallurgy R&D Unit

16555 Saticay StreetJet Propulsion Laboratory Van Nuys, CaliforniaCalifornia Institute of TechnologyAttention: Mr. B. P. Kohorst The Martin CompanyPasadena, California Attention: Manufacturing

Research & DevelopmentBaltimore 3, Maryland

- 43 -

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The Martin Company Northrop CorporationDenver Division Norair DivisionAttentions Chief 1001 East Broadway

Materials Eng. Hawthorne, CaliforniaMail No. L-8Denver 1, Colorado Oregon Metallurgical Corporation

Attention: Mr. S. M. Shelton,Materials Advisory Board PresidentAttention: Executive Director P. 0. Box 4842101 Constitution Avenue Albany, OregonWashington 25, D. C.

Pratt & Whitney Aircraft Corp.McDonnell Aircraft Corporation Attentions Metallurgical Eng. Dept.Attention: Chief Engineer East Hartford 8, ConnecticutLambert-St. Louis AirportP. 0. Box 516 Republic Aviation CorporationSt. Louis 3, Missouri Attention: Director,

Manufacturing ResearchNASA Farmingdale, Long Island, New YorkAttention: Materials Research Division1520 H Street, N. W. Rocketdyne DivisionWashington 25, D. C. North American Aviation Corp.

Attention: Department 574National Bureau of Standards 6633 Canoga AvenueAttention: Mr. A. Brenner Canoga Park, California

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-44 -

_TAPCO a division ofThompson Ran WOeldeIdge Irn.

Space Technology Laboratories U. S. Bureau of MinesAttentions Dr. Robert P. Felger Albany StationManager, Mechanics and Materials Attentions Mr. Eugene AssiP. o. Box 95001 Albany, OregonLos Angeles 45, California

Universal Cyclops Steel Corp.Special Metals, Inc. Refractomet DivisionResearch Librarian Bridgeville, PennsylvaniaNew Hartford, New York

Wah Chang CorporationStauffer Metals Company Attention: Mr. K. C. Li, Jr.Division of Stauffer Chemical Co. Vice PresidentAttention: Mr. G. W. Bauer 100 Church StreetTechnical Sales Manager New York 7, New York1201 South 47th StreetRichmond 4, California Waterton Arsenal Laboratory

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Westinghouse Electric Corp.Taylor Forge & Pipe Works 32 North Main StreetAttention: Special Products Manager Dayton 2, OhioP. 0. Box 485Chicago 90, Illinois Westinghouse Electric Corp.

Attention: Works ManagerThiokol Chemical Corporation P. 0. Box 228, AGT DivisionAttention: Mr. Patrick V. McAllister Kansas City, MissouriMaterials DepartmentMail Stop 240 Westinghouse Electric Corp.Wasatch Division Attention: DirectorBrigham City, Utah Space Material Dept.

Churchill BoroughTransue & Williams Steel Forging Corp. Pittsburgh 35, PennsylvaniaAttention: Mr. J. W. Ament

Sales Manager Wyman-Gordon CompanyAllience, Ohio Attentions Works Manager

North Grafton, MassachusettsUnion Carbide Metals CompanyDivision of Union Carbide Corporation Union Carbide Nuclear CompanyTechnology Department Attention: Mr. Paul E. Wilkinson4625 Royal Avenue, P. 0. Box 580 P. 0. Box YNiagara Falls, New York Oak Ridge, Tennessee

- 45 -

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