不同TIG重熔工艺对P275NL1钢焊接接头组织及性能的影响

Effects of different TIG remelting processes on the microstructure and properties of welded joints of P275NL1 steel

采用8组不同工艺参数对P275NL1钢焊接接头焊趾进行了TIG重熔处理,并通过金相显微镜和维氏硬度计对未重熔和重熔后的接头进行了微观组织观察和硬度测量。结果表明:未TIG重熔接头熔合区的组织中未发现有马氏体组织,而不同TIG重熔工艺接头重熔区的组织中均发现有马氏体存在。未TIG重熔处理的接头硬度最高值为HV220,而TIG重熔由于热输入小,重熔区冷却速度快,产生了淬硬组织马氏体,使组织硬度显著升高,最高达HV373。8组TIG重熔工艺中最合理的工艺参数为:焊接电流160 A,电弧电压15 V,重熔速度1.9 mm/s,热输入1263 J/mm。

TIG remelting treatment was carried out on the weld toe of P275 NL1 steel welded joints with 8 different process parameters,and the microstructure observation and hardness measurement of the unremelted and remelted joints were carried out by metallographic microscope and vickers hardness tester.The results showed that no martensite was found near the fusion line of the joint without TIG remelting,but martensite was found in the remelting zone of the joints with different TIG remelting processes.The maximum hardness of the joints without TIG remelting treatment was HV220,while the TIG remelting had a small line energy,insufficient heat input,and a fast cooling rate in the remelting zone,resulting in appearing martensite structure that significantly increased the hardness of the remelting zone,up to the highest HV373.The best process parameter among the 8 TIG remelting processes was:current 160 A,voltage 15 V,remelting speed 1.9 mm/s,and line energy 1263 J/mm.