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Great Designs in Steel is Sponsored by:AK Steel Corporation, ArcelorMittal Dofasco, ArcelorMittal USA,

Nucor Corporation, Severstal North America and United States Steel Corporation

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Investigation of Tooling Durability for Advanced High-Strength Steels

Tareena Mulholland-General Motors LLCDarryl Young-Ford Motor Company

Mike Klein-Chrysler LLC

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Team Members and Contributors

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Investigation Criteria

•Identify the tribological factors that contribute to the successful production of AHSS stampings

– Die Design– Die Materials– Surface Treatment– Cost Effectiveness

•Progressive Die with a two phase approach– Phase I: Form, Flange, Trim, Pierce– Phase II: Trim, Pierce

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Phase I

Lower Shoe Upper Shoe

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Phase I Description

Pier

ce

Pier

ce

Pier

ceTrim

Flan

ge

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Phase I Pierce Station

Location Material %Back-

up

1 M2/A2 5% 15%

2 M2/A2 10%

3 M2/A2 15%

4 M2/A2 20%

5 M2/A2 25% 15%

6 M2/A2 30% 15%

7 M4/A2 5% 15%

8 M4/A2 10%

9 M4/A2 15%

10 M4/A2 20%

11 M4/A2 25% 15%

12 M4/A2 30% 15%

13 A2/A2 20% 15%

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Phase I Pierce Results

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Phase I Trim Station

Material:1. CALDIE™ + Ion Nitride +PVD

TiCN2. CC® 1 (bar stock)3. CPM® 10V4. AISI D25. AISI M46. AISI S77. VANADIS® 4E

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Phase I Trim Results

Caldie™ (2), CC®1, HWS®

AISI D2, S7, M4NAAMS G25HP (2)

Incomplete Test

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Phase I Trim Results

Hardness may have direct effect on die material performance●

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Phase I Flange Station

Material:1. AISI D22. AISI D2 +CVD TIC3. CARMO® +Nitride

+PVD CrN4. AISI M25. AISI M46. AISI M4 + CVD TIC7. VANADIS® 4E

Maximum Strain

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Phase I Flange Results

• D2 + CVD TiC, M4 + CVD TiC, Carmo®+ Nitride + PVD CrN

• Materials D2, M2, M4, Vanadis®4E• Coatings PVD CrN, PVD TiAlN, Hard

Chrome, MicroPlasma

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Phase I Conclusions

• Pierce– Ideal clearance between 5-15%

• Trim– AISI D2 material performed the best– Coating did not seem to improve performance (only

tested for one instance)

• Flange– Coatings are necessary– PVD CrN performed better when applied over Ion Nitride

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From Phase I:• Scope too broad• Qualitative Wear• Inconsistent trim clearance

Improvements for Phase II:• Narrowed scope

• Quantitative Wear Analysis• Smaller inserts

Phase I Lessons Learned

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Phase II Description

PierceLong

Pier

cePier

cePier

ceLong

Pier

ceTrim

Pierce

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Phase II 1st & 2nd Pierce Stations

• Tested Punch Clearances

– 8%– 10%– 12%– 15%

• Tested Punch Materials– AISI D2– AISI M2– Vanadis® 4 Extra

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Surface Wear

Post DP980-20.0 – 20.0 μmPost DP780-2.00 – 2.00 μm

Pre-Test-2.00 – 2.00 μm

Measured Area• 1.5 mm x 0.63 mm• 8 measurements

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Pierce Clearance*

Pierce Material

Phase II Pierce Surface Wear

MaterialOriginal Surface

Post DP780Δ Roughness

Post DP980Δ Roughness

Post DP780% wear

Post DP980% wear

AISI D2 0.585 μm 0.155 μm 0.910 μm 26.5% 123.0%

AISI M2 1.644 μm 0.022 μm 0.377 μm 1.4% 22.6%

Vanadis® 4 Extra

0.629 μm -0.056 μm 0.258 μm -8.9% 45.0%

Break %Original Surface Post DP780

Δ RoughnessPost DP980Δ Roughness

Post DP780% wear

Post DP980% wear

8% 0.194 μm 0.145 μm 2.068 μm 75.3% 711.4%

10% 0.204 μm 0.066 μm 1.050 μm 27.7% 452.7%

12% 0.224 μm 0.043 μm 1.148 μm 22.5% 436.8%

15% 0.131 μm 0.024 μm 0.705 μm 3.0% 271.4%

* Values are averaged

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Phase II Trim Station

Trim tests• Trim angles from -30° to 30° in 5° increments• Materials: Caldie™, Vanadis® 4 Extra, AISI D2, ASP®2015,

and ASP®2015 + Everlast (patent pending process)

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Phase II Trim Results• All 30° trim angles began chipping at 19,000 hits or less

• Everlast extended the life of the ASP®2015 by at least 99.2%

211 Hits 8,530 Hits

18,000 Hits3 Hits 7,065 Hits

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Phase II 3rd Pierce Station

• Small round pierce– AISI M2– Pierce angles from -

30° to 30° in 5°increments

– Tools with controlled edge profile vs. a standard edge

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Phase II 3rd Pierce Results

• Pierce angle was most accurate indication of punch life; -15°< angle <15°

• Investigating quantifiable wear data from edge condition

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Phase II Conclusions

• Pierce– Ideal pierce clearance 15%– AISI M2 Material performed the best– Ideal pierce angles are between -15° and 15°

• Trim– Ideal trim angles are between -20° and 20°– Everlast extended the life cycle of ASP®2015

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Moving Forward

Future Work– Complete burr height analysis– Complete metallurgical analysis– Investigate optimal designs, materials, and coatings for

forming– Investigate significant differences between DP780 and

DP980– Continue to narrow the large selection of die materials &

surface treatments

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Questions?

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Great Designs in Steel is Sponsored by:AK Steel Corporation, ArcelorMittal Dofasco, ArcelorMittal USA,

Nucor Corporation, Severstal North America and United States Steel Corporation