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Corrosion Resistance of P/M S.St.

Corrosion Resistance of P/M S.St. Richard R. Phillips, Engineered Pressed Materials Dennis Hammond Apex Advanced Technologies, LLC. Objective. Using 316L, 17-4ph, 409LCb & 434L Achieve higher densities Higher densities at lower sintering temperatures Obtain good corrosion resistance.

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Corrosion Resistance of P/M S.St.

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  1. Corrosion Resistance of P/M S.St. Richard R. Phillips, Engineered Pressed Materials Dennis Hammond Apex Advanced Technologies, LLC

  2. Objective • Using 316L, 17-4ph, 409LCb & 434L • Achieve higher densities • Higher densities at lower sintering temperatures • Obtain good corrosion resistance

  3. History • Historically difficult to get high density • Compressibility limiting factor • Work hardening during pressing • High surface oxides on powder • Limited oxide reduction in sintering and densification • Lower densities interferes with corrosion resistance

  4. Water atomized 316L 3200 ppm O2 5200X

  5. Gas atomized 316L 150 ppm O2 5200X

  6. Powder Preparation • 100 mesh standard powders of 316L, 17-4ph, 409LCb & 434L • A group with 0.75 % Lithium Stearate • A group with an Activation Technology • TRS bars pressed at 690 Mpa (50TSI)

  7. Activation Technology • Blend Additive/Lubricant Master Batch • Hydrostatic distribution of additives & lubricant during compaction • Particles are aligned in a best fit arrangement • Density gradients eliminated • Activation is initiated in the delubing stage and finalized in the early stage of sintering

  8. Density Gradient – Shape Retention EPM

  9. Lithium stearate Activation Technology

  10. Compressibilityg/cm3 at 690 Mpa (50TSI) Material Li Str. Activation • 316L 6.83 6.76 • 17-4ph 6.28 6.23 • 409LCb 6.63 6.58 • 434L 6.51 6.47

  11. Processing • TRS bars delubed at 400OC (750OF) in Air • Sintering in a H2 box furnace with a slow cool > 1 hr. • Sintering in a continuous vacuum furnace with a 2 bar fast N2 quench < 10 min. • Sintered at: 1120 (2050), 1177 (2150), 1232 (2250), 1288 (2350), 1343 (2450) & 1388OC (2530OF) • Time at temperature 45 min.

  12. Atmosphere Box Furnace

  13. Continuous Vacuum N2 quench

  14. Sintering size change and densification

  15. ASTM B895 Standard for Test Method 2 For alloy screening and process optimization

  16. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  17. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  18. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  19. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  20. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  21. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  22. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  23. 0%A, <1%B, 1-25%C, >25%D 744 hrs. immersion in 5% NaCl

  24. Conclusion BETTER CORROSION RESISTENCE • Higher density • Faster cooling rate • Activation Technology Higher density at a lower temperature ` Better response with continuous Vacuum Best corrosion resistance

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