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Primary focus areas

Materials – composition and strength Heat treatment Residual stress Die coatings & surface treatments. H-13. June 7, 2000 Residual Stress Report. Primary focus areas. Develop means to reduce the softening effect during production cycling to improve die life

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Primary focus areas

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  1. Materials – composition and strength Heat treatment Residual stress Die coatings & surface treatments H-13 June 7, 2000 Residual Stress Report Primary focus areas

  2. Develop means to reduce the softening effect during production cycling to improve die life Develop means to Reduce build-up of residual stresses that contribute to premature failure Residual stress Task Force Goals

  3. Case western reserve university Ast – American stress technologies Pace industries Intermet – Ganton Ford motor company General motors powertrain Badger Metal Tech, Inc. Residual stress taskforce Facilitators & participants

  4. Residual stress task forceapproach • Develop baseline stress data • Must Perform on Production dies • Measure with x-ray diffraction and Barkhausen readings • Repeat until stress cracking initiates • Determine threshold values to indicate when maintenance or corrective action is needed

  5. 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 Current Test Site Pace Industries MOgm – cav 9,10

  6. Shot Biscuit Cavity #9 Approximate area where X-ray and Barkhausen measurements are being taken Directions #1 0 degrees # 2 -45 degrees # 3 -90 degrees Die Sampled 350 SHOTS Photos taken during Pace visit Prior to 1st #9

  7. Shot Biscuit Cavity #10 Approximate area where X-ray and Barkhausen measurements are being taken Directions #1 0 degrees # 2 -45 degrees # 3 -90 degrees Die Sampled 350 SHOTS REAR RETAINER Photos taken during Pace visit Prior to 1st #10

  8. Residual stressfirst measurement (Die already sampled - 350 shots) Procedure • Measurements taken by AST at specified areas determined by past history and Case Western recommendations • Die X-ray site plotted for future measurements • Barkhausen readings in same locations • Inserts returned to Pace for approximately 20-30K shots • Repeat measuring cycle for stress and Barkhausen readings until steel upsets & heat checking occurs

  9. Second Measurement • Die had 20,523 shots (producing castings (03/29/2000) (Will attempt to pull every 20-30K- takes 2 weeks) • AST commented that, upon receipt, noted that the calibration area selected on the dies for the 1st measurement appeared to be aggressively ground. • Same reference point used for measurement #1 would make Barkhausen readings (which measures change) not usable. • New calibration piece for reference was made by AST but not from (H-13). • Measurements taken and returned to Pace.

  10. third Measurement • Die has 41,209 shots 04-25-00 • Measurements taken and returned toPace on 05-03-2000. • Trend is Increasing toward zero for Xrd – More compressive ???? • decreasing for the bna. • Not what was expected • No physical signs of upset as yet

  11. Current readings trend indicates decreasing tensile stress

  12. Central Unit Sensor Apply Magnetic Field Detect B-signal Display and Output Barkhausen Noise Instrumentation Magnetize Amplify and Filter

  13. Barkhausen Noise Principle of Testing Magnetizing Voltage Central Unit Sensor Test Area Steel

  14. Amplitude Compression A2 A1 Tension   Stress   Amplitude Stress Barkhausen Noise Effect of Stress Low Amplitude High Amplitude

  15. Amplitude High Hardness A2 Hardness Rc Low Hardness Amplitude Hardness Barkhausen Noise Effect of Hardness Low Amplitude High Amplitude

  16. Recommended and Approved for Use by • SAE - Society of automotive engineering • Department of the Air Force • FAA - Federal Aviation Administration

  17. Future testing & studies • Continue testing cav #9 & #10 • Intermet (Ganton) – measure a four cavity die for ford Next phase • Metalife, dynablue • Surface treatment combinations • Various coatings – pvd & cvd

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