Effect of Alloy Additions on Wear Resistance of Nickel Based Hardfacing

摘要

The purpose of this research is to study the influence of the micro-structure and hardness of the nickel based hardfacing alloy on wear resistance of deposit layers when different alloy elements are added. Different deposit layers were obtained by SMAW in which AWS RNiCr bare electrodes were coated by fluxes, to which different measures of ferro-niobium, ferro-chromium, and carbon had been added. The resu It of the experiment showed that when subject to abrasive wear, if the abrasive particles were silicon carbide, the increase of the volume fraction of the hard phase had only a slight effect on improving the wear resistance of the deposit layers. However, if the abrasive particles were quartz, the increase of the volume fraction of the hard phase could improve the wear resistance of the deposit layers. On adhesive wear, the niobium added specimens formed some spherical niobium carbide particles in the matrix of the deposit layer which reduced the friction coefficient of the specimens. The addition of carbon and chromium can enhance macrohardness and wear resistance of the welding deposit significantly. This same addition will also aid wear resistance by forming a continuous phase in the microstructure of the deposit metal. While there was no significant difference between the ma-crohardnesses of the metals, the form of this precipitate in the deposit metals was actually the most important factor in their wear resistance. In the corrosion test, we found that increased carbon content reduced corrosion resistance to nitric acid. Increased chromium content helped to resist corrosion caused by nitric acid, but adversely affected corrosion resistance to hydrochloric acid.