Influence of Ni on hardenability of PM steels

摘要

Nickel is one of the most attractive and used alloying elements for high performance PM steels.The chemical composition of a wide variety of commercial Fe-based powders incorporates Ni,either, prealloyed or admixed. In the admixed condition, up to a concentration of 4%, Ni is anessential ingredient of diffusion bonded or binder treated powders, whereas in the prealloyedcondition it is usually contained, in lesser amounts, as part of the overall chemical compositionof the powder. In both cases Ni is aimed at conferring specific metallurgical characteristics tothe sintered steels but its influence is distinctly different depending on the way it is added. Thisis a consequence of the difference in the distribution of Ni finally leading to homogeneous orheterogeneous microstructures. This paper presents a study of the role of Ni on hardenability,microstructural development and mechanical properties of various PM steels.