Near Full Density Low Alloy Steel and Ductile Cast Iron by a New P/M Process

1. Near Full DensityLow Alloy Steel and Ductile Cast Iron by a New P/M Process Dennis Hammond Apex Advanced Technologies

2. Process Overview • Highly compressible, standard water atomized powder, pre-alloyed and straight iron • Special additive/lubricant master batch • Conventional blending, standard tooling and conventional pressing • Part pressing controlled to mass • Compaction range 45-55 TSI • Modified de-binding, controlledtemperature, time, and atmosphere

3. Process Overview Cont. • Modified sintering rate and temperatures up to 2500F for low alloy and 2200F for cast • Sintering atmosphere can be low % hydrogen or vacuum • Heat treating similar to conventional wrought and cast products • Lower alloying additions to achieve properties verses conventional P/M • Sintered densities >96%; up to 99+

4. Process Overview Cont. • Properties comparable/superior to wrought and cast products • MPIF standards for P/M structural parts will not predict properties, technology is more like a wrought/PM hybrid • Not all conventional P/M alloy systems are feasible with this technology. • Not all iron powders are suitable

5. Key FeaturesAdditive/Lubricant Master Batch • Calculations for feasibility of full density, desired lubrication, and needed additives • Target volume 98.5-99.5% of theoretical at target green density • Need for a green compact free of density gradients • Need for excellent lubrication, Apex Superlube® • Need for mobile lubricant to achieve best fit of metal particles during compaction and spread of additives

6. Key FeaturesAdditive/Lubricant Master Batch • Need for excellent distribution of additives in powder mix and compact • Need for excellent dispersion of additives • Need for no segregation of additives, particles charged during making the master batch • Master batch includes all additives including proprietary additives, pre-mixed and screened, ready to mix with iron powder

7. Key FeaturesAdditive/Lubricant Master Batch • Easy blending of additive master batch and metal • A.D. and flow of final mix may be not the same as a conventional mix • Static dissipative tubing should be use between the hopper and press, with grounding

8. Scope Mo, Ni, C Low Alloy Steels • Molybdenum range from 0.3% to 1.5% • Nickel range from 2% to 6.6% • Graphite .65% to .9%

9. Density DataLow Alloy Mo, Ni, C

10. Low Alloy MO, Ni, Cwith Martensitic Heat Treatment

11. Low Alloy MO, Ni, Cwith Martensitic Heat Treatment

12. Low Alloy MO, Ni, C with Three different Heat Treatments

13. Low Alloy MO, Ni, C with Three different Heat Treatments

14. Properties Observations • Low alloy content gives properties comparable to higher alloy content • It is possible to save on high cost alloy components Mo, Ni • Process gives properties far superior to comparable P/M conventional formulations • Process give properties superior to wrought and forged due to higher alloy content

15. Properties Observations • Heat treatment variation opens doors to modify properties to fit applications • A variety of surface treatments can now be used with this process due to the lack of porosity • Costly operations such as resin infiltration can now be eliminated

16. Scope Cr,Mo,Mn,Ni,C • Chromium .75% • Manganese up to .75% • Nickel up to 1% • Graphite .65% to .9%

17. Density DataLow Alloy Cr,Mo,Mn,Ni,C

18. Density DataLow Alloy Mo, Ni, C

19. Low Alloy Cr, Mo, Cwith Heat Treatments

20. Low Alloy Cr, Mo, Cwith Heat Treatments

21. Ductile Cast Iron • Base formula studied .7% silicon, 2% Graphite • Alloying components added with lubricant/additives as a master batch • Formula pressed green 6.95 to 7.00g/cc • Sintering 2180 F 25%hydrogen/75% nitrogen mixture, 7.67 g/cc as sintered, gray cast iron • Heat treated, similar to conventional cast 7.44g/cc after heat treatment (ductile cast)

22. Ductile Cast IronHeat Treated Gray Cast Iron • Easily machined • Low porosity, near full density • For machine applications with fair degree of toughness with high yield strength • Nodular cast iron possible • Many micro structures variations based on different heat treatments, ferritic, pearlitic, or martensitic

23. Gray cast iron as sintered, etched

24. Heat treated, etched

25. Dimensional Control Variables • Green density gradients - highly effective mobile lubricant, volume at G.D. • Elephant foot- caused by friction forces on support medium- reduced friction medium • Temperature –tendency to slump with temperature and time- controlled time and temperature • Liquid phase components- uniformity of component and temperature

26. Dimensional Stability Examples • High Nickel 4%,Mo,C • Part design, bushing 1.5 In. O.D.,1in I.D. height ~1inch • Ave. Density green 7.28g/cc • Ave. Density Sintered 7.79g/cc • Max. roundness top .002,mid .001,btm .002 inches • Max taper .003 inches

27. Dimensional Stability Examples • Nickel 2%,Mo,C • Part design, bushing 1.5 In. O.D.,1in I.D. height ~1inch • Ave. Density green 7.24g/cc • Ave Density Sintered 7.75g/cc • Max. roundness top .001,mid .001,btm .002 inches • Max. taper .002 inches

28. Dimensional Stability Examples • .75%Chromium, .25%Mo, .85%C • Part design, modified bushing 2.295 O.D., 1.186 I.D. .780 height • Ave. Density green 7.16g/cc • Ave. Density Sintered 7.65g/cc • Max. roundness top .002, mid.003, btm .002 • Max taper .003

29. Conclusions • New net shape processes may open significantly new applications for P/M • High levels of alloy content are not needed to get excellent physical properties • Properties allow for favorable comparison to cast, wrought and forged applications • Heat treatments can significantly modify properties

30. Conclusions • A variety of wrought surface treatments will be able to be used with this technology • Modifications to de- binding and sintering will slow introduction to the market • Combining heat treating with the sintering process will lead to higher flexibility, customizing properties and cost saving • Forward thinkers will be needed