Theoretical effects of heat treatment and minor elemental additions to AISI 420 martensitic stainless steels.

Martensitic stainless steels (MSS) meeting with the general requirements of the AISI 420 family can be through hardened and still exhibit some corrosion resistance. Even if they are generally not as resistant as austenitic stainless to localized corrosion, MSS including those generally covered by the AISI 420 designation, have been extensively used to produce components of injection molding dies and tooling. In these applications, wear resistance (with associated high hardness), dimensional stability and corrosion resistance are required for example to maintain tight molding tolerances and ensure acceptable surface finish. Some proprietary alloys manufacturers claim that minor additions of elements such as V, Ti, Mo and W can significantly improve the general properties of AISI 420 alloys. The effect of these minor additions will be discussed and reviewed both on a theoretical basis and using available literature. The effect of these minor additions on heat treatment behavior, resistance to sensitization and susceptibility to temper embrittlement will be discussed.