对液压支架用中厚Q960钢板进行焊接热模拟试验，分析了不同冷却速率（0.5~100℃·s^-1）下热影响区粗晶区的显微组织和硬度；通过铁研试验和焊接接头力学性能试验，对机器人焊接工艺进行了确定。结果表明：在焊前预热100℃条件下，当冷却速率低于80℃·s^-1，即焊接热输入大于6.5 kJ·cm^-1时，模拟得到热影响区粗晶区硬度可稳定在420 HV以下；在焊前100℃预热，焊接热输入为13.95 kJ·cm^-1条件下，机器人焊接Q960钢板接头具有良好的抗冷裂纹敏感性；匹配ER96-G焊丝，13.02~15.18 kJ·cm^-1焊接热输入下机器人焊接中厚Q960钢板接头的性能均能满足标准要求。适宜的机器人焊接参数为焊前预热100℃、焊接电流460 A、电压33 V、焊接速度60 cm·min^-1、送丝速度8.5 m·min^-1，此时焊接熔敷率可达到8 kg·h^-1。

The welding thermal simulation test was conducted on medium thick Q960 steel plate for hydraulic supports. The microstructure and hardness of the coarse-grained heat-affected zone under different cooling rates (0.5-100℃·s^-1) were analyzed. The robot welding process was determined by Tekken test and welded joint mechanical performance tests. The results show that the simulated hardness of coarse-grained heat-affected zone could be stabilized below 420 HV when the cooling rate was lower than 80℃·s^-1, namely the welding heat input was greater than 6.5 kJ·cm^-1 under the preheated temperature of 100℃. The Q960 steel plate joint welded by robot welding had excellent cold crack resistance sensitivity under the welding heat input of 13.95 kJ·cm^-1 and the preheated temperature of 100℃. The properties of robot welding Q960 steel plate joint could meet the standard requirements within the welding heat input of 13.02-15.18 kJ·cm^-1 with ER96-G welding wire. The recommended welding parameters for robot welding were listed as follows:preheating at 100℃, welding current of 460 A, voltage of 33 V, welding speed of 60 cm·min^-1 and wire feed rate of 8.5 m·min^-1, and the welding deposition rate could reach 8 kg·h^-1.