The indentation and wear performance of hardfacing layers on H13 steel for use in high temperature application

TBM (Full face rock tunnel boring machine) is a large tunnel excavation lining complete equipment which has been widely used in many practical fields. The main components of TBM rock breaking are the disc cutters. Due to the harsh working environment of TBM, such as high temperature (400°C), wear, etc., the consumption of disc cutters is extremely high. Two welding methods used to repair cutters of TBM were analyzed in this paper: shielded metal arc welding (SMAW) and flux cored arc welding (FCAW). The microstructure at RT was investigated, the hardness, indentation modulus and wear resistance from RT to 400°C were also investigated. The results showed that the microstructure of FCAW hardfacing layers was finer. In the tests, the FCAW hardfacing layers showed better hardness and elastic modulus, both parameters reduced with increasing temperature. The FCAW hardfacing layers processed higher wear resistance from RT to 400°C. A thick oxide layer was observed, and it was partially removed when the temperature reached 400°C, and it has a certain protective effect on the worn surface. Therefore, the FCAW hardfacing layers are considered as a good choice due to the better mechanical performance from RT to 400°C.