Effect of surface Cr/C infiltration on microstructure, mechanical properties and wear resistance of high chromium cast iron

Abstract

A new type of high chromium cast iron (HCCI) was prepared, and its microstructure, mechanical properties, and abrasion resistance were investigated systematically. Results showed that after surface carburizing and chromizing, the microstructure of HCCI mainly consists of martensite, boride (M2B), and carbide (M7C3), accompanied with a large amount of secondary precipitations M23C6. Moreover, the morphology and hardness of the carbide and boride in HCCI change little, while the volume fraction of carbide and boride increases from 16.23% to 23.16%. This effectively increases the surface hardness of HCCI from 64.53±0.50 HRC to 66.58±0.50 HRC, with the result that the surface of HCCI possesses a better abrasion resistance compared to the center position. Furthermore, the wear mechanism of HCCI changes from micro-plowing to micro-cutting with the increase of surface hardness.