Also known as X20Cr13, the 420 grade is a Martensitic type of stainless steel. Under normal circumstances it has an average corrosion resistance, but it may rust in tougher conditions. Stainless steels of this grade are attracted to magnets.

​

The most underlining quality of the 420 grade is its ability to harden with heat treatment. After heat treatment, it can reach significantly high hardness values. Even with its high carbon inclusion, the annealed 420 grade’s machinability is quite well. The annealed 420’s sawdust is brittle and will not spiral.