Abrasive wear of hardfaced ST52-3 steel hammer parts using mo-alloyed high chromium electrodes by SMAW

Abstract

This work studied the effect of Mo on abrasive wear resistance of (20-23) Cr-(7-8)Nb hardfaced St52-3 steel by shielded metal arc welding (SMAW). Four fluxes which compose of the fixed Cr and Nb but different Mo contents, coated on electrode were used. Microstructure, microhardness, and abrasive wear resistance test, following ASTM G65 procedure D, of the hardfaced surface were investigated. Primary coarse carbide and eutectic carbide are the main microstructure. Mo affects morphology of primary carbide by decreasing size. When Mo content of the hardfaced surface was up to 6.43 wt-%, the highest abrasive wear resistance and the highest microhardness were obtained. The decrease of primary carbide size by Mo addition is probably due to the increase of carbide nucleation. The network structure was also observed when the Mo content of the hardfacing surface reaches to 10.19 wt-%. The main wear mechanisms are microcutting and carbide pulling out.