Physical Property
Density ,g/cm3: 7.85
Specific heat capacity, J/(kg.K):460
Thermal conductivity ,W/(m.K):42
Electric resistivity,Ohm.mm2 /m:0.19
Modulus of elasticity ,Gpa: 210
Mechanical Property

Forging
Heat the temperature between 1050ºC-1150ºC,hold suitable time for the steel to be thoroughly heated.Reheat the steel once
temperature below 850°C. Crack is easily occured when improper cooling way after forged,so it should be cooled as slowly
as possible in the furnace or in sand after forged.
Heat Treatment
Soft Annealing
Heat to 650-720ºC, cool slowly in the furnace. This will produce a maximum Brinell hardness of 248.
Hardening
Harden from a temperature of 870-930ºC, followed by oil/polymer or water quenching.
Tempering
Tempering temperature: 580-700ºC.
Nitriding
Gas/plasma nitriding temperature (gas, salt bath): 570-580ºC
Gas/plasma nitriding temperature (powder, plasma): 580ºC
Surface hardness after nitriding: 800 HV

Application
31CrMoV9 nitriding steel is used in mechanics automotive and general mechanics, which must be nitrided for very high wear forces,
for example, gears, rods or axes.Structural parts of medium and large cross sections and high surface hardness, e.g., valve and
gate valves, cylinders for combustion engines, superheated steam valves and fittings.