1. Status of HCAT Integrity/Fatigue Testing John P. Sauer Sauer Engineering February 20th, 2002

2. Presentation Outline History Current and future work –Small/Big Bar Axial Fatigue/Coating Integrity –Bend Testing Goodrich Hill Process Control and Maturity Update-Almen Summary

3. History Spalling issue is the current show stopper Identified as an issue as we have moved form Boeing low load R =.1 testing to military directed higher load R = -1

4. Methods-Coating Integrity Four ways to address issue –Testing (Is it representative??) Type/size of specimen Method of testing axial vs. bend –Process/Material New coating chemistry/combinations Understanding how process can vary and the effect on spalling tendency

5. Axial Fatigue-Current Small axial bars have comprised the majority of the testing General 1 st thought in all protocols as all baseline substrate data based on this slight variations of this geometry Current threshold –180-200 ksi at R = -1 for.003 “thickness –160-180 ksi at R = -1 for.010 “thickness –Some limited work at Hill raises these numbers

6. Axial Fatigue Integrity testing regime is currently: –190 to 240 ksi –R ratio of -.5 to -1.0 –Run ???? cycle increments stepping 10 ksi after each cycle set-look for cracking, etc. –Stop at load when coating has spalled-save bar for analysis OR –When reach 240, cycle to failure

7. Axial Fatigue-Future More work on bars at Hill process that show higher threshold Work on three new coatings at.010” thickness –Self fluxing WCCo –NiAl as a bond coat –T-400 as a bondcoat

8. Axial Fatigue Big Bars Current Response to fact that small bars don’t represent real parts NAVAIR Big Bars –180 ksi R = - 1 threshold at.003” thickness –160 ksi R = - 1 threshold at.010” thickness HCAT Big Bars –Phil to cover

9. Axial Fatigue Big Bars-Future NAVAIR Big Bars (Eui will cover) HCAT Alternate coatings-.010” thickness- Hitemco ( depends on small bar results) –WCCo self fluxing –NiAl –T-400

10. Bend Testing Current COMPONENT ( more like real parts) Goodrich –Testing in progress Ben/Roque to discuss –More testing on pistons planned in future Hill –Bend testing on A-10 pistons shows good promise at up to 240 ksi R =-1 –More testing in progress

11. Bend Testing Future QC TYPE TESTING Goodrich Hollow bend specimen –3 pt bending Hill Hollow bend specimen –4 pt bending varied wall thickness

12. Current Issues-Higher stress-R ratios What are the exact cracking thresholds?? What exact factors affect the tendency to crack/delaminate/spall?? Testing or process parameters/variation??

13. Process Control and Maturity CURRENT STATUS Reliable process understanding below 180 ksi and R =.1 with no spalling issues Coating suppliers with Boeing (170 ksi R =.1) approval can supply coatings for commercial applications Meet the QC tests and use approved processes which are not system driven Many suppliers with varied processes approved

14. Process Control and Maturity NEW ISSUE With the identification of the spalling issue at higher loads, this same process reliability is not a given Current QC tests do not seem to give any indication about spalling behaviour Many processes within HCAT/CHCAT on variety of test programs

17. Process Control and Maturity How do we determine the reliability of the HVOF spray process with regard to spalling with so many parameter sets in the mix?? How do we rank one set of parameters vs. another or understand how a spray variable affects spalling? At this point, we don’t have the answers!!!

18. Process Control and Maturity

19. With this in mind, it is suggested we need to better understand the process and identify a screening test with regard to spalling Can it be a new QC test?? Bending?? –Volvo uses a bend test/count the cracks –Praxair uses acoustic emission

20. Process Control and Maturity A plan is now being considered that dovetails both the need to understand the process and evaluate the best test methods to make this happen (Jean Gab/John/Keith) It will evaluate the many parameter sets used within HCAT and work to develop the needed screening test to determine spalling tendencies The ultimate outcome would be a QC screening test

21. Process Control and Maturity This will address our ultimate goal for process control in production: –If a set up meets initial fatigue qualification and QC tests, it doesn’t matter what parameters are used –This will mean varied guns, fuel gases, and parameter sets will be approved This work needs to be done!!

22. Almen/Temp Previous presentation presented summary on HCAT endorsed method of crosswise/grit blast both sides Temp measure tech is critical especially for spot size in measuring fatigue bars Recent work indicates depo rate is another key issue New document available on website as part of LG JTP report

23. Summary Issues still exist at R =-1 and higher stress levels Must work on: –Test methods –New materials –Process understanding This will allow us to solve the spalling issue