The temperature dependence of the wear resistance of iron-base NOREM 02 hardfacing alloy

The sliding wear behavior of an iron-base NOREM 02 hardfacing alloy was investigated in the temperature range of 25–300°C under a contact stress of 103 MPa (15 ksi). The wear resistance of NOREM 02 was comparable to that of Stellite 6 at temperatures below 180°C, and the dominant wear mechanism was mild oxidative wear. With increasing temperature, however, the wear mode of NOREM 02 changed abruptly to severe adhesive wear at 190°C and galling occurred above 200°C. It was found from microhardness variations beneath the worn surfaces that the abrupt decrease of wear resistance is due to the loss of work hardening ability. X-ray diffraction and TEM analyses of the worn surfaces showed that a strain-induced phase transformation from austenite to a′ martensite took place below 180°C while not above 190°C. Thus, it was concluded the development of strain-induced a′ martensite plays an important role in the wear resistance of an iron-base NOREM 02 hardfacing alloy.