Soumya Subramonian Evaluation of Stamping Nimet Kardes ...€¦ · Soumya Subramonian Nimet Kardes...

Soumya Subramonian

Nimet Kardes

Yurdaer Demiralp

Center for Precision Forming (formerly ERC for

Net Shape Manufacturing–ERC=NSM),

The Ohio State University,

339 Baker Systems,

1971 Neil Avenue,

Columbus, OH 43210

Milan JurichHonda of America Mfg., Inc.,

Corporate Planning,

24500 Honda Parkway,

Marysville, OH 43040

e-mail: [email protected]

Taylan AltanCenter for Precision Forming (formerly ERC for

Net Shape Manufacturing – ERC=NSM),

The Ohio State University,

339 Baker Systems,

1971 Neil Avenue,

Columbus, OH 43210

e-mail: [email protected]

Evaluation of StampingLubricants in FormingGalvannealed Steels forIndustrial ApplicationLubrication is one of the process variables that affect the quality of stamping sheetmaterials. Using a good lubricant can significantly reduce scrap rate and=or improve thequality of stamping. In this study, different types of lubricants were evaluated using stripdraw test (SDT) and deep draw test (DDT) for stamping of galvannealed steel sheets.Finite element (FE) simulations were carried out to determine the coefficient of friction attool-work piece interface during deep drawing under different lubrication conditions andblank holder forces. Flow stress data of materials under biaxial load which are used in FEsimulations are obtained by viscous pressure bulge tests. SDT was used as a preliminarytest to evaluate the relative performance of the lubricants. Lubricants that showed goodperformance in this test were tested using DDT. Dimensions of the formed strips and cupsand the maximum applicable blank holder force to draw parts without fracturing were thecriteria used for evaluation of lubricants in both tests. In general, it was possible to formcups with higher blank holder force when synthetic=water-based lubricants were appliedto the sheet. In conclusion, evaluated synthetic=water-based lubricants had better lubricitythan petroleum-based lubricants. [DOI: 10.1115/1.4003948]

Keywords: stamping, lubrication, galvannealed draw quality steels

1 Introduction

There are various tribotests that are used to evaluate the per-formance of stamping lubricants.As these tests are performedunder laboratory conditions, it is important that they emulate theconditions found in stamping plants. The tribotests widely used toevaluate lubricants include strip draw test (SDT), draw bead test,sliding test, and limited dome height test. Strip reduction test wasintroduced by Andreasen et al. [1] and was used to evaluate lubri-cants for galling of the tool while ironing stainless strips. Twistcompression test was used by many investigators [2] in order toestimate the coefficient of friction (COF) of stamping lubricants.Many of the above tests fail to emulate real-world production con-ditions in terms of contact pressure, plastic deformation of thesheet material, temperature, and forming velocities. These factorsinfluence the performance of the stamping lubricant and henceneed to be considered while choosing a test to evaluate lubricants.The deep draw test (DDT) used in this study to evaluate thestamping lubricants represents very closely the conditions thatexist in the production of sheet metal parts. Therefore, it wasselected for this study. However, SDT was also used for prelimi-nary selection from a large number of lubricants.

The overall objective of this study is to select a lubricant that willhelp in reducing scrap rate while stamping galvannealed (GA) andgalvannealed=prephosphate steel used in various North Americanplants of a major car manufacturer. The specific objectives are to:

(1) Evaluate the various stamping lubricants under near-production conditions

(2) Select lubricants that perform well for stamping GA steels

(3) Determine the coefficient of friction at tool-work pieceinterface under different lubrication conditions through fi-nite element (FE) simulations.

2 Experiments, Analysis, and Results

All the lubricants in this study were evaluated first using theSDT, which works on the same principle as the DDT.When alarge number of lubricants need to be evaluated, SDT is a goodpreliminary test. The lubricants that performed well in SDT wereevaluated using DDT (Fig. 1). DDT was used as the decisive testin order to evaluate the lubricants. Preliminary FE simulationswere conducted before SDT and DDT to determine the optimaltest conditions. FE simulations were also compared with experi-mental results in order to determine the coefficient of friction fordifferent lubrication conditions [3].

2.1 SDT. Strip draw test shown in Fig. 2 was previously usedby Kim [4] in order to evaluate galling on the tool surface whileforming advanced high strength steels. In this test, two die insertsare used in order to draw the strip. Die corner radius of 5 mm isselected to achieve severe test conditions. Figure 3 shows the halfmodel of a drawn strip, 81 mm in depth, and U-shaped. The crite-rion used to evaluate performance of the lubricant is strip elonga-tion. The smaller the strip elongation (i.e., smaller the thinning ofthe specimen), the better is the lubrication condition.

A good lubricant will reduce the COF and this will decrease thepunch force and the strip elongation. In addition, varying the coef-ficient of friction using different lubricants and blank holderforces (BHFs) will result in a wide range of friction forces basedon the Coulomb’s law given by Eq. (1),

s ¼ l � Pb (1)

Contributed by the Manufacturing Engineering Division of ASME for publicationin the JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING. Manuscript receivedDecember 1, 2009; final manuscript received March 14, 2011; published onlineNovember 11, 2011. Assoc. Editor: Zhongqin Lin.

Journal of Manufacturing Science and Engineering DECEMBER 2011, Vol. 133 / 061001-1Copyright VC 2011 by ASME

Downloaded 18 Nov 2011 to 140.254.212.150. Redistribution subject to ASME license or copyright; see http://www.asme.org/terms/Terms_Use.cfm

Fig. 1 Flow chart for lubrication evaluation

Fig. 2 Schematic of strip draw test [4]

Fig. 3 Configuration of specimen and die insert in SDT [4]

Table 1 Parameters used in FE model to determine workingrange of BHF in SDT experiments

Parameter Description

Sheet material 270D=GAStrength coefficient (K) 598.12 MP a for r¼Ken

Strain hardening exponent (n) 0.2541Blank size—Length�Width 356 mm� 254 mmThickness 0.75 mmBlank holder force (ton) 3, 5, 7, 9Coefficient of friction (between blankholder and sheet, die and sheet)

0.05–0.09

Stroke 81 mm

061001-2 / Vol. 133, DECEMBER 2011 Transactions of the ASME


where s is the frictional shear stress, l is the coefficient of friction,and Pb is the blank holder pressure.

2.2 Finite Element Simulations for Strip DrawTest. Different lubrication conditions correspond to differentCOF at the tool-workpiece interface.Hence, FE simulations wereconducted with PAMSTAMP 2G [5] in order to determine the BHFthat can be applied during SDT without necking or fracturing byobserving the change in draw-in lengths and punch forces at dif-ferent COFs for different BHFs [6]. Parameter used for the simu-lations is given in Table 1.

From Table 2, it was seen that a BHF of 3–5 ton does not causenecking. Fracture or forming limit was assumed to be reached at24% maximum wall thinning. BHF of 5 ton showed more varia-tion in draw-in length and punch force across different COFs thanBHF of 3 ton. Thus, it was determined that in the present experi-mental setup, 3–5 ton BHF was a good working range for SDTbased on Table 2.

2.3 Experimental Set-Up and Testing Condition

2.3.1 Description of the Tooling. The strip drawing toolingwas placed in a 160 metric-ton hydraulic press that has a maxi-mum ram speed of 300 mm=s (Fig. 4). The die inserts (Fig. 3)

attached to the upper ram moved down to form a strip over a sta-tionary punch. The preset constant BHF was applied by the CNC-controlled hydraulic cushion pins. During the test, the punch forcewas measured by a load cell located at the bottom of punch andthe displacement of the die inserts was recorded by a laser sensor.

2.3.2 Test Procedure. Strips of dimensions 356 mm� 25.4mm� 0.75 mm were deep drawn to take the shape shown inFig. 3. The BHF to be applied was decided based on FE simula-tions Table (2). Strips were drawn for various lubrication condi-tions, and the length of deformed strip was measured for each con-dition. Analysis of the results based on strip elongation was usedto evaluate the performance of the lubricants.

2.3.3 Lubricant Selection and Application. In this study, fif-teen lubricants and two washer oils were evaluated, four of thelubricants failed in the tests for chemical stability and cleanability.The remaining 21 conditions (mill oilþwasher oilþ lubricant)were evaluated using SDT Table 3 gives the types and codes oflubricants evaluated in these series of tests.

The lubricants were applied on the strips by using a pipette anddraw-down bar for uniform application. Lubricants were appliedto a coating weight of 1.5 (6 0.3 gm=m2). This was determinedby measuring the strip weight before and after the application ofthe lubricant.

2.3.4 Test Conditions. The BHF used in the tests wereselected based on the results of FE simulations (Sec. 2.2). During

Table 2 Results of FE simulations of SDT showing the variation in punch force and draw-in length as a function of COF and BHF

COF

BHF (ton)

3 5 7 9

Max punchforce (KN)

Draw-inlength (mm)

Max punchforce (KN)

Draw-inlength (mm)

Max punchforce (KN)

Draw-inlength (mm)

Max punchforce (KN)

Draw-inlength (mm)

0.05 4.61 61.40 6.60 59.43 8.48 55.46 10.48 47.540.06 5.33 60.77 7.60 57.94 10.00 50.51 Fracture Fracture0.07 6.03 60.15 8.76 55.3 Fracture Fracture Fracture Fracture0.08 6.82 59.54 9.92 51.73 Fracture Fracture Fracture Fracture0.09 7.32 58.81 11.00 45.66 Fracture Fracture Fracture Fracture

Fig. 4 Strip draw test tooling [4]

Table 3 Types of lubricants evaluated using SDT

Synthetic lubricant L1, L11, L12, L13Semisynthetic lubricant L10Water-based lubricant L6, L15Petro-based lubricant L7, L8, L9, L14

Table 4 Test conditions used in SDTs

Sheet material DQ 270F-GA=prephosphate,DQ 270F-GA,

DQ 270D-GA=prephosphate,and DQ 270D-GA

Sheet thickness, width,and length (mm)

0.75, 25.4 6 0.2, and 356 6 0.5

Die material (hardness) Uncoated graphite cast iron (38 HRC)Surface roughness ofdie insert

�0.2 lm

Stroke 81.7 mmBHF 3 tonRam speed 10 mm=sNumber of samples pertest condition

5

Table 5 Thicknesses and average plastic anisotropy ratios (R)of sheet materials (provided by the steel supplier, Arcelor-Mittal)

Sheet material Thickness (mm) R

DQS 270D-GA=prephosphate 0.75 1.85DQS 270D-GA 0.75 1.85DQS 270F-GA 0.75 1.98DQS 270F-GA=prephosphate 0.75 1.98

Journal of Manufacturing Science and Engineering DECEMBER 2011, Vol. 133 / 061001-3


SDT, BHF of 3 ton gave significant differences in draw-in lengthfor different lubrication conditions. The ram speed for testing waschosen to be 10 mm=s because it was the maximum speed at 3 tonBHF that the strip could be formed. Table 4 gives the conditionsunder which strip draw test was conducted. Table 5 gives the ani-sotropy values and thickness of the sheet materials used in thisstudy.

2.4 Results of Strip Draw Tests. The variation in strip elon-gations was used to evaluate the different lubrication conditionsfor all four sheet materials Table 5. The average strip elongationsand the variations (five specimens) observed for different lubri-cants after drawing are shown in Fig. 5. It was also found that thelubricants performed almost the same on all the four sheet materi-als used.

M indicates mill oil that was applied on the sheet by the steelsupplier, while W2 and W3 indicate washer oils. Based on theresults of the SDT, the test matrix for DDT was determined.

2.5 DDT—Principles. Deep draw tests were conducted byKim et al. [7] in order to evaluate stamping lubricants in formingadvanced high strength steels (AHSS). In deep drawing, the mostsevere friction usually takes place at the flange area as shown inFig. 2. The lubrication condition in the flange area influences (1)thinning and possible failure of the sidewall in the drawn cup and

(2) draw-in length, Ld, in the flange (Fig. 6). As the blank holderpressure, Pb, increases, the frictional stress, s, also increases basedon Coulomb’s law, as shown in Eq. (1). Therefore, lubricants canbe evaluated in deep drawing by determining the maximum appli-cable blank holder force without fracture in the cup wall.

The two criteria used to evaluate lubricants in DDT are

(1) Maximum applicable blank holder force without fracture inside wall

(2) Draw-in length in the flange (larger the draw-in length, bet-ter the lubricant). This is equivalent to measuring the flangeperimeter (smaller the perimeter, better the lubrication).

2.6 FE Simulations for Deep Draw Test. FE simulationswere conducted in order to predict (i) the applicable range ofblank holder forces in deep drawing experiments and (ii) the coef-ficient of friction at the tool-blank interface.

FE simulations were conducted using the software DEFORM-2D[8] in order to determine the applicable range of BHF for deepdraw tests based on the maximum thinning for different COFs atdifferent BHFs. The flow stress data of the materials wereobtained using biaxial viscous pressure bulge test [9] (Appendix).A range of 0.05–0.07 was used for COF based on previous studies.Range of 20–40 ton BHF was used in the FE simulations based onthe studies conducted by Kim et al. [7]. From the SDT experi-ments, it was found that the strip fractures after thinning of 28%.Hence, this value was used as the criterion to determine the

Fig. 5 Results of strip drawing tests, average elongation of all materials for various lubrication conditions used(strips cracked while using lubricant L14)

Fig. 6 Schematic of deep draw test



workable range of BHF. The FE model and results used are seenin Fig. 7 and Table 6.

As seen in Table 6, a range of 20–30 ton BHF would be suitableto carry out deep draw tests. Since a difference in thinning wasobserved for various COF, there would be variation in draw-inlength for different lubricants.

FE simulations were carried out with PAMSTAMP 2G after thedeep draw experiments in order to predict the coefficient of fric-tion at the tool-blank interface, using the parameters given inTable 7. PAMSTAMP 2G was used instead of DEFORM 2D because itwas much faster while giving comparable results. Because of axi-symmetry, only one quarter of the cup was modeled in finite ele-ment analysis (FEA), as seen in Fig. 8. The flange perimeterobtained at the end of stroke in the simulation is compared withthe flange perimeter obtained in the experiment. This was used todetermine the coefficient of friction from the simulation. Theresults are given in Sec. 2.9.

2.7 Experimental Set-Up and Test Conditions. The tool-ing used in deep draw test is the same as that used for strip drawtest except that the die inserts were replaced with a round drawdie. In deep drawing tooling, the die corner radius is 16 mm andthe diameter of the die cavity is 158.2 mm (Fig. 6).

2.7.1 Test Procedure. Round blanks of 305 mm were drawninto round cups as shown in Fig. 9. The perimeter of the flange of

the cup was measured. Cups were drawn with different lubricationconditions at different BHFs. The perimeters of cups drawn at thesame BHF were compared for evaluation. With “better” lubri-cants, cups can be drawn at higher BHFs. Maximum punch forcewas also recorded in the tests.

2.7.2 Lubricant Selection and Application. Selection of lubri-cants for deep draw test was done based on the results of strip drawtests. The lubricant was applied using a pipette and draw down bar.Lubricant coating weight of 1.5 (6 0.3) gm=m2 was maintained.The lubrication conditions for the tests were selected to emulate theapplication of lubricants in stamping plants using rollers.

2.7.3 Test Conditions. Blank holder forces for deep drawtests were selected based on the results of FE simulations. Thus,the range of 20–30 ton BHF was found to be suitable for the tests.Ram speed for testing was around 40 mm=s, which is close to thespeeds of production presses. Table 8 shows the test parametersfor deep drawing experiments.

2.8 Results of Deep Draw Tests. The lubricants were eval-uated based on (1) maximum blank holder force at which cupscan be drawn without fracture and (2) perimeter of the flange ofthe cup. The perimeter of cups drawn using different lubrication

Table 6 Maximum thinning % at 80 mm of stroke, as predictedby FE analysis

BHF (ton)

COF

0.05 0.06 0.07

20 15 17 1530 20 19 2940 29 Possible fracture

at 75 mm of strokePossible fracture

at 65 mm of stroke

Table 7 Parameters used in FE model to predict COF in DDT


Sheet material 270D=GAStrength coefficient (K) 598.12 MP a for r¼Ken

Strain hardening exponent (n) 0.2541Blank size—Diameter 304.8 mmThickness 0.75 mmBlank holder force (ton) 20, 22, 24Coefficient of friction (betweenblank holder and sheet, die and sheet)

0.06–0.1

Stroke 79.5mm

Fig. 7 Axisymmetric model of the tooling used in DEFORM-2Dsimulations

Fig. 8 Quarter model of the DDT simulated using PAM-STAMP

Fig. 9 Schematic of deep drawing tooling

Table 8 Parameters of the deep draw tests


Sheet material 270D=GA (0.75 mm thickness)Blank size 305 mm diameterBlank holder force (ton) 20, 22, 24Ram speed 40 mm=sStroke 79.5 mmNumber of samples 5–10 (based on the consistency of

perimeter of the cups drawn)Lubricants L1, L6, L9, L10, L11, L15, L16, L17



conditions at the same BHF was compared for evaluation. A lubri-cation condition was said to have failed at a certain BHF if thecup fractures.

Figures 10–12 give the flange perimeter and punch forcerecorded for the different lubrication conditions at different BHFs.Lubricants that sustained higher BHFs were classified as “good”lubricants. For the same BHF, the lubricants that gave lowerflange perimeter were considered as “better” lubricants.

The experimental results showed that the water-based lubri-cants L6 and L15 performed well while in general, syntheticlubricants and water-based lubricants performed better than petro-leum-based lubricants. Although this might not be obviously intui-tive, the newly developed synthetic and water-based lubricantswith additives showed better performance in comparison with tra-ditionally used petroleum-based lubricants.

It can also be observed that the BHF also affects the flange pe-rimeter for the same lubricant. This is because different BHFswould lead to a different contact pressures between the blank andthe blank holder. The properties of the lubricants may changewith the contact pressure and temperature. Lubricants with pres-sure and temperature additives tend to perform better at higherBHFs while the others may not.

2.9 Determination of COF at Tool-Blank Interface. Theflange perimeter of the cups obtained from experiments and FE

simulations of deep draw test was compared in order to determinethe coefficient of friction at tool-blank interface for different lubri-cation conditions and different BHFs. The coefficient of frictionwas assumed to be the same at both the blank-blank holder inter-face and the blank-die interface since the COF at the two interfa-ces is unknown and could not be determined.

In Fig. 13, the two circled values showed the flange perimeteras obtained from FE simulations for COF 0.09 and 0.1. The flangeperimeter obtained for COF 0.09 in FE simulation was 753 mmwhich was about the same for lubrication condition MþL15.Hence, COF while using MþL15 is about 0.09. Similarly, COFwhile using MþL9 is 0.1. The COF while using the other lubri-cants were calculated using the same procedure. Figure 13 illus-trates the comparison of flange perimeter estimated by FEA forCOF of 0.08 and 0.09 with experimental data for BHF of 22 ton.

Similarly, Fig. 15 compares the flange perimeter predicted byFEA with experimental data for BHF of 24 ton.

Figures 13–15 illustrate that

(1) There was a noticeable difference in the coefficient of fric-tion at the tool-sheet interface for different lubricants at thesame BHF.

(2) The coefficient of friction was reduced with increase inBHF for the same lubricant. This has been found out bycomparison of experimental and simulation results. COFdepends on the surface finish of the two materials in con-tact. The surface finish of the softer material (blank) may

Fig. 10 Flange perimeter and punch force recorded for 11 lubrication conditions at 20 ton BHF(M 1 L18 failed at 20 ton BHF)

Fig. 11 Flange perimeter and punch force recorded for fourlubrication conditions at 22 ton BHF (samples of other lubrica-tion conditions failed)

Fig. 12 Flange perimeter and punch force recorded for twolubrication conditions at 24 ton BHF (L1 and L10 failed at 24ton)



Fig. 13 Comparison of flange perimeters obtained from simulation and experiment to predictthe coefficient of friction at 20 ton BHF





vary at higher BHFs. Some flattening of the peaks mayoccur in the blank at higher BHF, resulting in an impro-ved=smoother surface and hence reducing the COF. A simi-lar effect has also been shown in Ref. [10], where PAM-STAMP simulations were conducted and the effect of COFon BHF was studied.

3 Discussions

It is important to recognize the conditions in which parts arestamped in the industry in order to evaluate lubricants becauselubricants behave differently under different stamping conditions.Some of the aspects to be considered are:

3.1 Lubricant Application Method and Quantity. It is im-portant to make sure that the lubricant is evenly distributed on thesheet metal for the required amount. The amount of lubricant ofthe sheet surface affects the quality of stamped part. Hence, opti-mal amount of lubricant needs to be applied depending on the

(1) amount of lubricant that can be applied on the sheet underproduction conditions,

(2) amount of lubricant required to stamp “good” parts.

In this study, a pipette was used to make sure that there isrepeatability in the amount of lubricant applied and draw downbars were used to ensure uniform distribution of lubricant on thesheet metal specimens. Hence, consistency was maintained withina sample and between samples.

3.2 Die and Blank Holder Surface. In this study, the blankholder surface was polished to a surface roughness (Ra) of 0.25–0.35 lm. The dies used in this study had a surface roughness (Ra)of 0.2 (6 0.2) lm. Kim et al. [11] measured the surface roughnessof a die used for forming the outer panel of an automobile andfound that the Ra value varies from 0.21 to 1.39 lm. Further, theyobserved that the coefficient of friction does not decrease withdecreasing surface roughness. Instead, the COF was found to belowest at the surface roughness Ra value of 0.3 lm.

3.3 Blank Holder Force=Binder Force. The blank holderforce used in the experiments should be comparable to those usedin production conditions. In this study, BHF of 20–24 ton wasused in order to draw DQS cups of 12 in. diameter and over a dieradius of 0.63 in. This is comparable to the forces used in thestamping industry. The amount of blank holder force has a signifi-cant effect on the quality of the stamped part.

3.4 Ram Speed. The speed at which the ram travels has animportant effect on the drawability of the part. Additionally, somelubricants perform differently at different speeds, due to heat gen-erated at the sheet-tool interface. Hence, it is important that theexperiments are done at speeds comparable to that used in produc-tion environment. Ram speed of about 40 mm=s used in this studyis comparable to the average ram speed encountered in productionstamping presses.

4 Summary and Conclusions

4.1 Summary

(1) Several lubricants were evaluated for stamping DQS 270grades of steel.

(2) Strip draw test was used for preliminary evaluation anddeep draw test was used as a conclusive test for the evalua-tion of lubricants.

(3) The criteria used for evaluation was (i) maximum blankholder force and (ii) strip length in strip draw test andflange length in deep draw test.

(4) Coefficient of friction was determined for different lubrica-tion conditions and blank holder forces by comparing theresults of FE simulations with experimental data.

4.2 Conclusions

(1) The strip draw tests and deep draw tests were successful indifferentiating the performance of different lubricants undernear-production conditions.

(2) The tests revealed that lubricants L15 and L6 performed thebest and lubricants L10 and L1 were next best.

(3) In general, the studies showed that water-based=syntheticlubricants performed better than petroleum-based lubri-cants. In this test, synthetic lubricants have better lubricitybecause they have high pressure and temperature additivesthat improved their performance. However, the exact com-positions of these additives as well as that of all the lubri-cants tested are proprietary and they are not available fromthe lubricant suppliers.

(4) Simulations revealed that the coefficient of friction reducedwith increase in BHF when all other conditions remainedunchanged.

Acknowledgment

The authors gratefully acknowledge the support of HONDA ofAmerica Manufacturing Inc.

Appendix: Viscous Pressure Bulge (VPB) Test

VPB tests were carried out in order to obtain the biaxial flowstress data of the materials used in the FE simulations conductedin this study. The schematic of VPB tooling is shown in Fig. 16.The flow stress curves (Fig. 17) were used in the finite elementsimulations. Details on the viscous pressure bulge test can befound in Ref. [9].

Fig. 16 Schematic of the tooling used for VPB test; before andafter bulging of the sheet [9]

Fig. 17 Flow stress data obtained from VPB test



References[1] Andreasen, J., Bay, N., Andersen, M., Christensen, E., and Bjerrum, N., 1997,

“Screening the Performance of Lubricants for the Ironing of Stainless SteelWith a Strip Reduction Test,” Wear, 207(1–2), pp. 1–5.

[2] Kim, H., Sung, J., Goodwin, F. E., and Altan, T., 2008, “Investigation of Gal-ling in Forming Galvanized Advanced High Strength Steels (AHSS) Using theTwist Compression Test (TCT),” J. Mater. Process. Technol., 205(1–3), pp.459–468.

[3] Subramonian, S., Kardes, N., Demiralp, Y., Billur, E., and Altan, T., 2009,“Evaluation of Stamping Lubricants to Improve Stamping Quality,” TheOhio State University, Columbus, OH, Technical Report No. CPF–2.5=09=02.

[4] Kim, H., 2008, “Prediction and Elimination of Galling in Forming GalvanizedAdvanced High Strength Steels (AHSS),” Ph.D. thesis, The Ohio State Uni-versity, Columbus, OH.

[5] www.esi-group.com, 2009, Web page of ESI group that develops and distrib-utes PAMSTAMP software.

[6] Kardes, N., Demiralp, Y., Groseclose, A., Subramonian, S., Al-Nasser, A.,Gonzalez-Zuniga, A., and Altan, T., 2009, “Evaluation of Stamping Lubri-cants to Improve Stamping Quality—Part I,” The Ohio State University,Columbus, OH, Technical Report No. CPF–2.5=09=01.

[7] Kim, H., Altan, T., and Yan, Q., 2008, “Evaluation of Stamping Lubricants inForming Advanced High Strength Steels (AHSS) Using Deep Drawing andIroning Tests,” J. Mater. Process. Technol., 209(8), pp. 4122–4133.

[8] www.deform.com, 2009, Web page of the SFTC that develops and distributesDEFORM software.

[9] Gutscher, G., Wu, H., Ngaile, G., and Altan, T., 2004, “Determination of FlowStress for Sheet Metal Forming Using the Viscous Pressure Bulge (VPB)Test,” J. Mater. Process. Technol., 146(1), pp. 1–7.

[10] Choudhury, I. A., Lai, O. H., and Wong, L. T., 2006, “PAM-STAMP in theSimulation of Stamping Process of an Automotive Component,” Simul.Model. Pract. Theory, 14(1), pp. 71–81.

[11] Kim, D. D., Kim, B. M., Lee, Y., and Min, B. H., 2002, “Friction Characteris-tics for Surface Finish and the Stoning Direction of Stamping Dies,” Proc.Inst. Mech. Eng., Part B, 216(4), pp. 531–542.



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http://dx.doi.org/10.1016/j.simpat.2005.04.002

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