Durability analysis of Laser-Arc Composite Welded Joints in Coal Mining and Tunneling Equipment

To ensure the stable service of coal mining and excavation equipment under complex working conditions and improve the long-term application performance of cutting head welding nodes of coal mining and excavation equipment, the durability of laser arc composite welding nodes of coal mining and excavation equipment is studied. Selecting ZG270-500 cast steel for cutting head body and 20CrNiMo alloy structural steel for cutting tooth seat as research objects, using ERNiCr-3 nickel based welding wire, a laser arc composite welding process was designed. Welding specimens were prepared with welding speeds of 30, 40, 50, and 60mm/s as variables, and mechanical properties, bending properties, and high-temperature endurance properties of the specimens were tested. The test results show that when the welding speed is 40mm/s, the tensile strength of the welded joint is 835.76 ± 10.34MPa, the impact absorption energy is 55.42 ± 3.08J, and it has excellent mechanical properties; And there are no obvious defects in bending, with long fracture time and low shrinkage rate in high temperature environment, and the best comprehensive durability; However, other speeds may experience varying degrees of performance degradation due to heat input or cooling issues. Therefore, a welding speed of 40mm/s can effectively improve the durability of the cutting head welding node.