Böhler M390 microclean 3.5x40x500mm

Böhler M390 microclean 3.5x40x500mm

M390 Microclean by Böhler is a stainless powder steel. M390 is know for its cutting edge performance, high corrosion resistance and moderate toughness. Can easily be polished to a mirror finish.

A very high 1.90% of carbon and advanced alloying elements make this a more complicated steel to heat treat. The payoff is the edge performance is the completed blade.

Heat treatment:

• due to long soak times, wrap blade securely in stainless steel foil to reduce carbon loss
• Preheat to 760-770 C and hold until certain entire blade is at temperature
• Rapidly increase temperature to 1170 C and hold for 30 minutes at temp
• Quench in oil or plates
• Cryo treatment before tempering increases hardness*
• Temper as soon as possible at 200 C for 2 hours, cool and temper for another 2 hours 

This will without cryo give a hardness of about HRC 59 and with deep cryo about 61 HRC

This is the heat treatment recipe provided by Topham