Martensitic Stainless Steel and Where Hardness Wins

How the Transformation Works

At normal quenching temperature martensitic stainless steels sit in the gamma phase zone, but that phase is only stable at high temperature. The martensite start point is generally around 300 C, so the structure transforms to martensite as the steel cools. That is why the family behaves like ordinary alloy steel when it comes to hardening.

Grades in the Family

The family includes 2Cr13, 2Cr13Ni2 and 3Cr13, along with partially modified 12 percent chromium hot strength steels such as 13Cr14NiWVBA and Cr11Ni2MoWVB. Their mechanical properties, corrosion resistance, process properties and physical properties are similar to ferritic martensitic grades containing 12 to 14 percent chromium.

Related product: 410 Stainless Steel Bar

Why They Are Stronger Than the Ferritic Martensitic Types

Because there is no free ferrite in the structure, mechanical properties are higher than in the comparable ferritic martensitic steels, and overheat sensitivity during heat treatment is lower. That combination is what makes them practical to heat treat in production.

Free Machining Grade 416

Grade 416, UNS S41600, is a free cutting martensitic stainless whose domestic designation is Y1Cr13. It is used on automatic lathes and is applied mainly in the production of electromagnetic components, micro motors and electrical parts, where machining rate matters more than maximum corrosion resistance.

Selecting a Grade and a Treatment

Because martensitic grades harden by quenching, a wide range of mechanical properties can be obtained by choosing the grade and the heat treatment condition together. Within the broader iron chromium carbon family they divide further into martensitic chromium stainless steels and martensitic chromium nickel types.

Related product: 301 Stainless Steel Bar