1.4021 / DIN X20Cr13 – AISI 420 – UNS S42000

1.4021 / AISI 420 grade stainless can be hardened by heat treatment like many high carbon steels. It contains at least 12% chromium (Cr) and this alloy is sufficient for corrosion resistance. It has good softness in the annealed state, but it has the ability to get 50 Rockwell hardness by heat treatment. It needs to be hardened and the surface cleaned or polished for best corrosion resistance.

Hardness (HB) 230 (max) Annealed 0.2% Yield Strength. (N / mm2) 500-550 Hard + Temper Tensile Strength. (N / mm2) 760 (max) Annealed Tensile Strength (N / mm2) 700-950 Hard + Temper% Elongation 13-10 Hard + Temper

Usage areas; Fork, knife, spoon, knife blade, surgical instruments, needle valve, scissor mouth etc.

Heat Treatment Condition; Annealing - full annealing - 840-900 ºC, slowly lowered to 600 ºC in the furnace and then cooled to air temperature.

Annealing process is heated between 735-785 ºC and air cooling, hardening 980-1035 ºC and then water is given with air or oil. Oil quenching is required for large sections. The temperature is brought between 150-370 ºC in order to reach the properties and hardness level specified in the mechanical properties table. Care should be taken that the heating limit is 425-600 ºC.

The hot forming temperature is 1100-850 ºC.

In terms of machinability, Martensitic stainless steels are the most suitable group for high hardness. It has poor weldability and usually requires hardening and tempering after welding. Corrosion resistance is lower than the austenitic group. The material should be efficient and should not be used at subzero degrees (loses its softness) and high temperatures (decreases durability). It can be processed well in its annealed form. However, after hardening (especially above 30 HRC), its workability becomes difficult.

The information given in this data sheet about the condition or availability of the material is not a guarantee for its properties, it only serves as an explanation. The information provided as advice is consistent with our own experience as well as general experience. No guarantee is given for the processing and application results of the products.