As-sintered AISI 440C stainless steels with improved hardness and corrosion resistance


Preliminary work on powder metallurgy (PM) AISI 440C steel with 1.2 w/o C indicated that it is possible to achieve acceptable hardness in the as-sintered condition, but with inferior corrosion resistance. To address this limitation, a series of simulations were carried out using Thermocalc software to predict alloy compositions and sintering temperatures for achieving optimum properties. The simulations served as the basis for the design of a Taguchi trial run with an L9 orthogonal array. Test samples were characterized utilizing microindentation hardness and salt-spray-corrosion testing. Microstructural analysis was also used to characterize and interpret the observed behavior. The results show that AISI 440C with 0.95 w/o C and 200 ppm B sintered at 1,220°C gives an optimum combination of the assintered roperties.
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