WEAR PROPERTIES OF (FE, CR)7C3 CARBIDE BULK ALLOYS

(Fe, Cr)7C3 carbide bulk alloys with different chromium contents were prepared by melting pure materials. Abrasion wear resistance of the carbide alloys was examined using a pin-on-disk type wear tester in relation to microstructure and hardness. Hardness and wear resistance of the carbide alloys were raised with increasing the chromium content and the dependence of wear resistance on hardness was seen remarkably under a low applied load. For the alloys with microstructures consisting of (Cr, Fe)7C3 carbide and retained austenite, a linear relationship was seen between wear resistance and the volume fraction of carbide up to the fraction of unity, but not between wear resistance and hardness. It was also found that the carbide alloys have a relatively large coefficient of thermal expansion comparable to steels and thus a strong bonding with substrate metals can be expected for an application of carbide alloys as a hardfacing material.