Microstructure and abrasive wear behaviour of shielded metal arc welding hardfacings used in the sugarcane industry

摘要

The abrasive wear behaviour of hypereutectic and hypoeutectic based Fe-Cr-C hardfacings are reported and interpreted in terms of the microstruc-tures. The coatings were deposited onto a grey cast iron substrate by shielded metal arc welding using two commercial hardfacing electrodes. The abrasive wear resistance was performed on a modified block-on-ring machine that simulated the wear conditions experienced in a sugar cane mill, Microstructural studies were carried out using optical and SEM techniques. It was found that the hardness of the hypereutectic coating was significantly higher than the hypoeutectic coating. In both cases, optimum hardness was achieved within the first deposited layer. The abrasion tests showed that there was no significance difference in the wear resistance of the hardfacings at the higher loads and there was contrasting wear behaviour in the dry and slurry conditions. The abrasive wear mechanisms were found to be predominantly microploughing and microcracking in the hypoeutectic and hypereutectic coatings, respectively.