Research and Application of Welding Technology for Q960 High-strength Steel

Q960 high-strength steel, as the core structural material of high-end equipment such as special vehicles and heavy engineering machinery, the rationality of its welding process directly determines the service reliability of the components. In response to technical challenges such as welding cold crack sensitivity and heat affected zone performance degradation caused by high carbon equivalent and high alloy content of Q960 high-strength steel, this paper systematically conducts weldability analysis of Q960 high-strength steel, compares the adaptability of mainstream welding methods such as manual arc welding, submerged arc welding, and CO ₂gas shielded welding, and constructs a process control system from three levels: pre weld pretreatment, welding parameter control, and post weld heat treatment. Prevention and control technologies for cold cracks and heat affected zone embrittlement are proposed, and the effectiveness of the process plan is verified through mechanical property testing and microstructure characterization of welded joints. The research results show that the process combination of low hydrogen welding materials, 150−200 ℃ preheating before welding, 15−25 kJ/cm line energy control, and 250−300 ℃ post weld hydrogen removal treatment can make the yield strength of Q960 high-strength steel welded joints ≥900 MPa and the low-temperature impact energy at −40 ℃≥30 J, meeting the service requirements of key components such as special vehicle frame beams. This provides theoretical support and process reference for the engineering application of Q960 high-strength steel.