Development and Welding Thermal Simulation Test of the Structural Steel Q460D for High Heat Input Welding

The structural steel Q460D for high heat input welding was trial-manufactured by using a 50 kg vacuum electrical furnace,a small-sized experimental rolling mill and other equipments.Cu,instead of Mo and Cr,was the main strengthening element of the steel plates,so the cost of plates was effectively controlled.The steel plate was smelted by using Ti deoxidation process,and then after controlled rolling,controlled cooling and tempering treatment,final products were obtained.The steel plates under different tempering temperature were studied by mechanical property tests and welding thermal simulation test.The results show that when the temperature of tempering treatment was 610℃,the strength and toughness of the plates match best.Under 100~120 kJ/cm high heat input welding conditions,the-20℃ low temperature impact energy of the welding coarse-grained heat-affected zone(CGHAZ) of the plates so produced is greater than 100 J,and the CGHAZ strength is not less than the substrate.