THE EFFECT OF MULTILAYER HARDFACING BY SMAW WITH AND WITHOUT PREHEAT ON THE HARDNESS AND WEAR RESISTANCE OF HARDOX 500 STEEL PLATE

• Main Author: Parulian Sinaga, Edwardt
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/39522
• Institution: Institut Teknologi Bandung

Bark crusher is an equipment used to convert the bark into optimal size particles, which utilized as the boiler fuel. Hummer and bottom grate are the main component in the bark crusher that have high wear rate during the process. High wear rate is the main reason to applied the hardfacing on the surface of the component. This study has two main purposes, first to understand the effect of the multilayer welding, which using high chromium alloy as the electrode, to the hardness and the wear resistance of hardfacing, and secondly to investigate the influence of preheat on hardfacing layer characteristic. Observation and characterization methods were done to acquire the chemical composition, microstructure, hardness and wear resistance of the hardfacing specimen. Optical emission spectroscopy (OES) has been used to get the actual chemical composition of the second and fourth hardfacing layer. The morphology or microstructure of hardfacing was observed by metallography, especially to observed the presence of iron carbides in the weldment. The presence of carbides will affect the hardness and wear resistance of the hardfacing. The result of chemical composition and microstructure showed that hardfacing with four layer have carbon and chromium in high consentration and tend to have the iron carbide M7C3 in high fraction. The hardness increasing of hardfacing is strongly affected by the presence of iron carbide M7C3, which proven by hardness test to all spesimens. Errosion wear test conducted with the airjet errosion tester using Al2O3 (50 um) particles as the erodent and the result indicated that the speciment with the largest primary carbide M7C3 fraction has better wear resistance.