Vacuum heat treatment, deep cryogenic treatment and simultaneous pulse plasma nitriding and tempering of P/M S390MC steel

► Deep-cryogenic treatment (DCT) improves the microstructure of high-speed steel. ► After DCT higher surface hardness and better wear properties are obtained. ► Longer DCT increases surface hardness, but has limited effect on tribology. ► Selection of the proper austenitizing temperature prior DCT is very important. ► By simultaneous DCT and nitriding, further improvements can be obtained.