1. Mar 5, 2003 Residual Stress Report
Phase II focus area
Residual stress targeting
Heat treatment
Materials – composition and strength
Die coatings & surface treatments
H-13

2. Residual Stress Taskforce March 5, 2002 Report Phase II Participants
Dave Thomason – Pace Mo
Vince Adkar - Thyssen
Curt Kyonka – Pace mo
James Pineault – Proto Mfg.
Michael Brauss – Proto mfg.
Dr. David Schwam – Case Western
Jerry Skoff – Badger Metal Tech

3. Long Term Goals Of The Develop means to predict and reduce
the softening effect during production cycling to improve die life
build-up of residual stresses that contribute to premature failure of die tooling

4. Residual Stress Taskforce Facilitators
Case Western Reserve University
Proto Manufacturing
Pace Industries (beyond baseline)
Badger Metal Tech, Inc.

5. Residual Stress Task Force Approach
Develop baseline lab data using x-ray diffraction measuring.
Test on production dies
Determine threshold values to indicate when die maintenance or corrective action is needed

6. Residual Stress Task History
Developing baseline lab stress data that will be confirmed in the field
Some x-ray measurements recorded
Tests on 2 Production dies (MN and MO) that did not support expectations. Baseline testing may help support earlier data.
Unsuccessful in determining failure threshold on any production dies

7. Hypothesis I - Cycling
Tensile stresses build until they are relieved by development of small micro-cracking
Tensile readings drop after this and then stress BUILDS again.
Once again cracking develops and TENSILE again dropS in value. (CONTINUE UNTIL VISIBLE CRACKING)
If this is true, READINGS will show a cyclic decrease in tensile stress because of the above phenomenon.

8. Hypothesis iI - Flex
THE NORMAL CYCLING OF THE DIE PUTS THE DIE THROUGH TENSION AND COMPRESSION values
The acceptable and followed current consensus is that tensile stress causes thermal cracking and failure
THIS CYCLING, EVEN THOUGH NOT MAXIMIZED EVENTUALLY CAUSES THE DIE TO UPSET

9. Hypothesis iII - Decarb
The generation of continued cyclic high temperatures cause a loss of carbon at the surface (decarb)
The die softens and loses toughness due to the decarb
Continued temperature cycling results in build-up of tensile stresses
Yield is exceeded and die surface upsets

10. All corners square +.003” to -.003” All corners have .010” radius
Baseline Testing
Pre - Dip tank testing
virgin specimen
nothing applied
thoroughly polished
send to proto for x-ray diffraction
corner measurements
case western specified where proto was to take measurements
baseline measurements taken
H-13
Dip Tank
Specimen 2”
each
side 7”
All corners square +.003” to -.003”
All corners have .010” radius

11. Cycling & measurement Dip tank testing Immersion aluminum
12 seconds immersion
24 seconds air cool
Water based lube 50:1
Repetitive cycles
X-ray diffraction measure
Take micro hardness before and after readings
measure for corner cracks
Photograph x-ray MEASURED surface area
H-13
Dip Tank
Specimen 2”
each
side 7”
Photography not performed on this 1st specimen
All corners square +.003” to -.003”
All corners have .010” radius

12. X-Ray Readings Last 06/11/02
Dip Cycle measurement performed at Zero,10,100,500,1000,5000, 10000, and now will be measured after cycles
Current Data lent itself to a cycle measurement, specimen now has cycles on it but not measured yet.

13. Proto X-Ray Reading Criteria
location measurements
Corners 1,2,3,4,5,6,7,8
Middle – 1,3,5,7
Each corner measured at 3 points
Each middle measured at 3 points
45o at point #2 (middle) – only for zero cycles
Measurements in ksi -1ksi = 6.895Mpa
Error range ∓ 5 with average ∓ 2 (zero-1000)
Error range ∓ 8 with average ∓ 5 (5000 cycles)
Error range ∓ 8 with average ∓ 4 (10,000 cycles)
Error range ∓ 2 with average ∓ 1 (15,000 cycle)

14. Phase ii – Baseline Testing
Side 5
Side 7
Side 3
Measured corners
6ea per side x 4 = 24 points
Measured middle side 1,3,5,7
Axial 3ea per side x 4 = 12
Trans 3ea per side x 4 = 12
Total of 48 x-ray diffraction measurements from 36 locations
Side 1
3.5” 2”
each
side
H-13
Dip Tank
Specimen 1”
.5”
3.5”
1.0”
All corners square +.003” to -.003”
All corners have .010” radius

15. No Dip Cycles - Baseline
All but 4 measurements indicate compression

16. Compressive Stress turns to Tensile
10 Cycles
Compressive Stress turns to Tensile

17. Tensile stress values reduced
100 Cycles
Tensile stress values reduced

18. Tensile stress again increasing
500 Cycles
Tensile stress again increasing

19. Tensile stress approaching values seen at 10 cycles

20. Tensile stress continuing to increase
5000 Cycles
Tensile stress continuing to increase

21. Tensile stresses at highest levels
10000 Cycles
Tensile stresses at highest levels

22. Tensile stress drop off again – by larger amount
15000 Cycles
Tensile stress drop off again – by larger amount

23. Measurements to be taken at this cycle point
20000 Cycles
Measurements to be taken at this cycle point
Proto will measure
Die Materials Meeting
March 5, 2003

24. SUMATION CURVES and Individual through 15,000
Stress v/s Cycles
Normal
Stress v/s Cycles
Logarithmic
(cannot be zero)

25. What do we know ?
Cycling of tensile stresses
starting small compression changes rapidly to tensile
stresses increase between 100 & cycles
Tensile stress reading at dramatically drops
data could support one or combination of hypothesis

26. Conclusions will continue to measure at 20K and 30K
more test specimens
measure dislocation densities via peak width
micro hardness changes (multiple specimens)
measure corner cracking (before 1st and after)

27. Future Lab Testing Last at Case - 1/31/2003
Will perform additional testing?
Go beyond the 20,000 dips?
Measure corner cracking
Important not to polish or change stress profile

28. Future Field Test Parameters
No polishing or other modifications to tooling during test cycles
Micro-analysis of surface for cracks
Shorter measurement cycles
Last shot castings should accompany dies and be retained for comparison at case western
Micro-hardness readings

29. Mar 5, 2003 Residual Stress Report
baseline testing
H-13