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Standardization of Testing and Process Evaluation

Standardization of Testing and Process Evaluation. John P. Sauer JoPSauer@Fuse.Net SAUER ENGINEERING December 13, 2000. Workscope Standardization/Correlation Almen/Temp Measurement Bar Configuration Almen Range Testing Conditions NDT Residual Stress Analysis

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Standardization of Testing and Process Evaluation

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  1. Standardization of Testing and Process Evaluation John P. Sauer JoPSauer@Fuse.Net SAUER ENGINEERING December 13, 2000

  2. Workscope • Standardization/Correlation • Almen/Temp Measurement • Bar Configuration • Almen Range • Testing Conditions • NDT • Residual Stress Analysis • 4 Point Bend Analysis (strain to failure) Sauer Engineering www.SauerEngineering.com

  3. Common goal • Replace hard chrome • Different reasons/methods • Application • Past database for evaluation • Varying philosophy Sauer Engineering www.SauerEngineering.com

  4. Protocols • NWU-Generic • Landing Gear JTP • HCAT • CHCAT • Propeller Hub • PEWG • Actuator Sauer Engineering www.SauerEngineering.com

  5. Test Methods • Almen • Temp measurement • Metallography (Automatic) • Tensile • Fatigue • Wear • Corrosion Sauer Engineering www.SauerEngineering.com

  6. Reaching for • Standardization • Same methods • Realistic target • Correlation • Different methods • Common evaluation set • Tie protocols together Sauer Engineering www.SauerEngineering.com

  7. Fatigue • Standard Almen/Temp Method • Standard Bar Configuration/Coating Location • Realistic Almen Range for Each Coating • Standard Test Conditions Sauer Engineering www.SauerEngineering.com

  8. Almen Measurement • Data from conversations with HCAT members • Spraying at VAC AERO, CTS, Southwest, and Hill AFB • Procedure written Sauer Engineering www.SauerEngineering.com

  9. Orientation • Crosswise • Lengthwise • Grit Blasting • None • One side • Both sides • Almen Measurements • Fixtures • Magnetic • Screw type • Rotating? • Normalize • None • Thickness .005” Sauer Engineering www.SauerEngineering.com

  10. Almen Measurement • Decision made to standardize on the method as highlighted • Must have correlation to HCAT method • Run side by side comparison Sauer Engineering www.SauerEngineering.com

  11. Almen Measurement • Recent work has shown: • Grit blast one side(non HCAT) vs. both sides (HCAT) 4 mil difference • Lengthwise (non HCAT) vs. crosswise (HCAT) 1-2 mil difference Sauer Engineering www.SauerEngineering.com

  12. Temperature Measurement • Spot size • Develop method for compensation(Really bigger) • Emissivity • Develop setting and leave alone • Real and Catch all • Recording • Use RS 232 port for continuous recording and set intervals as fast as possible (.015 sec/reading) • Background • Consistency (Black block of wood possibility) Sauer Engineering www.SauerEngineering.com

  13. Temperature Measurement • Calibration • Method • Contact probe • Maximum temperature • 300 vs. 350 F Sauer Engineering www.SauerEngineering.com

  14. Standard Bar • Configuration • Smooth • Coating Location • Patch coating Sauer Engineering www.SauerEngineering.com

  15. Almen Range • WCCo 6-12 mils • WCCoCr 6-10 mils • Simulate part spray thermal history or just a process check?? Sauer Engineering www.SauerEngineering.com

  16. Testing Conditions • R = - 1.0?? • Load range of 180 ksi to runout?? Sauer Engineering www.SauerEngineering.com

  17. Degree of Correlation • Good Correlation • NWU to HCAT Landing Gear • Minimal Correlation • CHCAT LG (Plans to address) • Propeller Hub JTP (Small test bar sample) Sauer Engineering www.SauerEngineering.com

  18. Degree of Correlation • Difficulty • Problem solving issue-cannot rely on past • Different sets of data are non-usable to others Sauer Engineering www.SauerEngineering.com

  19. NDT • Two individual inspections • FPI on chrome more for “grinding damage” and circumferential “gross” defects • MPI on substrate thru chrome-any indication is rejectable • Two possible inspection times • During initial production • May also be an inspection after service Sauer Engineering www.SauerEngineering.com

  20. NDT • Two issues • Can current methods find same substrate defects detected under chrome also under the HVOF? • What is the degree of concern on this issue? Sauer Engineering www.SauerEngineering.com

  21. Listing of views from varied sources • Cherry Point • No problem-assume HVOF will behave just like chrome • with current inspection scheme • Jacksonville • Will not perform any repair inspection as received from • field-only after stripping, HVOF and regrinding • Hill AFB • There arerequirements for base metal under • chrome-don’t find defects because they believe • inspection will find nothing under .125-.250” Sauer Engineering www.SauerEngineering.com

  22. Listing of views from varied sources • Delta • No real history on HVOF yet-for chrome, always • stripped so no real data on exists for in use cracking • thru chrome plating • Boeing Seattle • Looking at Barkhausen as method for inspection • Boeing St Louis • Concern over lack of understanding for this subject- • research is planned and funding being sought Sauer Engineering www.SauerEngineering.com

  23. Bottom Line • No unified answer on what we need to find-no definition of POD and process capability • No real “level of concern” for base metal defects-no current issues exist-have usaually stripped chrome in rework • No standards or samples exist for chrome and HVOF for testing • No new vendors on possible NDT methods are willing to spend time on a “moving” target Sauer Engineering www.SauerEngineering.com

  24. NDT methods • Work in progress at • Boeing/MDC(Barkhausen)Wes Graham/Clint Surber • AFRL(Current techniques)Joe Kolek/Stefan Susta • Varied other sources(Heroux) • Developing standards for future use • Using new methods will probably only be for spot/high stress areas Sauer Engineering www.SauerEngineering.com

  25. Residual Stress • What are the true levels in the parts? • Almen is a guideline but not real magnitude • What is best test method? XRD, MLRM, ??? • Preliminary work is needed to provide baseline data Sauer Engineering www.SauerEngineering.com

  26. Sauer Engineering www.SauerEngineering.com

  27. Residual Stress • Planning limited work correlating Almen vs. as sprayed blocks • Establish relationship with major gun suppliers on 2-3 runs-then rely on Almens Sauer Engineering www.SauerEngineering.com

  28. 4 Point Bend • Can be used to establish strain to failure data for coating • Method usually involves use of acoustic emission on a (.25 x .5-1.0 x 6.0-10.0”) specimen to determine onset of cracking Sauer Engineering www.SauerEngineering.com

  29. 4 Point Bend • General number currently being quoted is about .5-.7% for WCCo and WCCoCr • Plans in progress to perform some current analysis at Hamilton Sundstrand and as part of HCAT/CHCAT spalling investigation Sauer Engineering www.SauerEngineering.com

  30. 4 Point Bend • Striving to determine standard test specimen/method • Presentation later by Shane Arthur/John Quets of Praxair Sauer Engineering www.SauerEngineering.com

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