1 / 15

Primary focus areas - 2001

Materials – composition and strength Die coatings & surface treatments Heat treatment Residual stress. H-13. March 14, 2001 Residual Stress Report. Primary focus areas - 2001. Dave Thomason – Pace Mo Jim berry – pace mo Curt kyonka – pace mo Bob ehrman – ast

melva
Download Presentation

Primary focus areas - 2001

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Materials – composition and strength Die coatings & surface treatments Heat treatment Residual stress H-13 March 14, 2001 Residual Stress Report Primary focus areas - 2001

  2. Dave Thomason – Pace Mo Jim berry – pace mo Curt kyonka – pace mo Bob ehrman – ast Dr. David Schwam – Case Western Jerry Skoff – badger metal Tech Residual stress taskforceMar 14, 2001 reportparticipants

  3. Develop means to predict and reduce the softening effect during production cycling to improve die life Develop means to predict and Reduce build-up of residual stresses that we now believer contribute to premature failure of die tooling Goals of the

  4. Case western reserve university Ast – American stress technologies Pace industries General motors powertrain ? Badger Metal Tech, Inc. Residual stress taskforce Facilitators & participants

  5. idealistic Residual stress task force approach • Develop baseline lab stress data • Test on Production dies • Measure using x-ray diffraction and possibly Barkhausen readings • Determine threshold values to indicate when die maintenance or corrective action is needed

  6. Realistic Residual stress task comments • No baseline lab stress data that can be confirmed in the field • 2 Tests on Production dies (MN and MO) that did not support expectations • Scattered inconsistent x-ray and bna readings • Unsuccessful in determining failure threshold on any production dies

  7. high volume runner multiple cavities flat surface prone to h/c history of rapid h/c flexible production schedule smaller size inserts for handling reasonable time frame for results approval of end user Historical data II Pace Industries MOgm – cav 9,10 satisfied attributes and criteria

  8. FOURTH final Measurementrecap • Die has 86,209 shots 08/15/2000 • Measurements taken and returned to Pace on 08-25-2000. • Trend indicator averages moving more toward zero for Xrd – More compressive • Mixed readings for bna measurements • Not what was expected • DIEs NOW SHOW signs of upset in RUNNER AREA Testing stopped

  9. all readings No definitive trend with some Increasing & decreasing tensile stress

  10. hypothesis i • 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) • Appearance from READINGS show a decrease in tensile stress because of the above phenomenon.

  11. hypothesis iI • THE NORMAL CYCLING OF THE DIE PUTS THE DIE THROUGH TENSION AND COMPRESSION • The acceptable and followed current assumption is that tensile stress causes cracking and failure • THIS CYCLING, EVEN THOUGH NOT MAXIMIZED EVENTUALLY CAUSEs THE DIE TO UPSET

  12. Where do we go from here? • Dip tank testing? • X-ray diffraction • Prescribed cycles • Measure corners Or • measure flats • Take micro hardness before and after • Photograph x-ray MEASURED surface area H-13 Dip Tank Specimen 2” each side 7” All corners square +.003” to -.003” All corners have .010” radius

  13. Future testing & studies • Should we wait on “big 3” findings through national labs ? (if data is made available to us) • Is it valuable to have case western utilize the dip tank test to: • Measure stress changes ? • Measure with x-ray and/or bna ? • Measure micro hardness ? • Historical photomology study ? • How do we test in the lab to obtain data we can use ?

  14. Some Criteria to consider for future Production dies • No polishing or other modifications to tooling during test cycles • Micro-hardness readings prior to and after all shot intervals • Micro-analysis of surface for cracks • Shorter measurement cycles • Last shot castings should accompany dies and be retained for comparison at case western

  15. General Committee consensus at this time • sabbatical on future production die tests until we have more data or a definitive course of action based on future available data from other organizations • Same for proposed lab testing until we can Develop some type of base line criteria and format based on above data

More Related