TESTING STANDARDIZATION Standardization of Testing and Process Evaluation John P. Sauer...

TESTING STANDARDIZATION

Standardization of Testing and Process Evaluation

John P. Sauer

[email protected]

SAUER ENGINEERING

December 13, 2000

December 13, 2000 Sauer Engineeringwww.SauerEngineering.com


HCAT December Update 2

• Workscope– Standardization/Correlation

• Almen/Temp Measurement

• Bar Configuration

• Almen Range

• Testing Conditions

– NDT– Residual Stress Analysis– 4 Point Bend Analysis (strain to failure)




• Common goal– Replace hard chrome

• Different reasons/methods– Application– Past database for evaluation– Varying philosophy




Protocols

• NWU-Generic

• Landing Gear JTP– HCAT– CHCAT

• Propeller Hub

• PEWG

• Actuator




Test Methods

• Almen

• Temp measurement

• Metallography (Automatic)

• Tensile

• Fatigue

• Wear

• Corrosion




• Reaching for – Standardization

• Same methods

• Realistic target– Correlation

• Different methods

• Common evaluation set

• Tie protocols together




Fatigue

• Standard Almen/Temp Method

• Standard Bar Configuration/Coating Location

• Realistic Almen Range for Each Coating

• Standard Test Conditions




• Almen Measurement

– Data from conversations with HCAT members

– Spraying at VAC AERO, CTS, Southwest, and Hill AFB

– Procedure written




• Almen Measurements

– Fixtures• Magnetic• Screw type• Rotating?

– Normalize• None• Thickness .005

”

–Orientation•Crosswise•Lengthwise

–Grit Blasting•None•One side•Both sides




• Decision made to standardize on the method as highlighted

• Must have correlation to HCAT method

• Run side by side comparison

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

Almen Measurement




• 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)




• Temperature Measurement

– Calibration• Method

– Contact probe

– Maximum temperature– 300 vs. 350 F




Standard Bar

• Configuration– Smooth

• Coating Location– Patch coating




Almen Range

• WCCo 6-12 mils

• WCCoCr 6-10 mils

• Simulate part spray thermal history or just a process check??




Testing Conditions

• R = - 1.0??

• Load range of 180 ksi to runout??




Degree of Correlation

• Good Correlation– NWU to HCAT Landing Gear

• Minimal Correlation– CHCAT LG (Plans to address)– Propeller Hub JTP (Small test bar sample)




Degree of Correlation

• Difficulty

– Problem solving issue-cannot rely on past

– Different sets of data are non-usable to others




• 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




• 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?




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 are requirements for base metal under chrome-don’t find defects because they believe inspection will find nothing under .125-.250”




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




• 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




• 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




• 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




• 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




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




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




4 Point Bend

• Striving to determine standard test specimen/method

• Presentation later by Shane Arthur/John Quets of Praxair

TESTING STANDARDIZATION Standardization of Testing and Process Evaluation John P. Sauer...

Documents

Transcript of TESTING STANDARDIZATION Standardization of Testing and Process Evaluation John P. Sauer...