氮气比例对金属粉末再压缩等离子弧焊接电弧电压和焊缝成形的影响

Impact of Nitrogen Gas Proportion on Arc Voltage and Weld Formation in Plasma Arc Welding with Additional Focusing by Metal Powder

目的探索金属粉末再压缩等离子弧焊接中氮气比例对焊缝成形、焊缝硬度的影响规律,指导316L不锈钢金属粉末再压缩等离子弧焊接工艺。方法首先搭建和完善金属粉末再压缩等离子弧焊接实验平台;其次,重点考虑氮气对金属粉末再压缩等离子弧焊接的影响,并根据氮气比例的不同针对性地进行实验设计,实验Ⅰ中氮气体积分数为0,实验Ⅱ中氮气体积分数为8%,实验Ⅲ中氮气体积分数为16%;最后开展焊接实验并对焊接接头进行相关测试和分析。结果当氮气体积分数为16%时,焊缝熔深相较于纯氩气焊接的焊缝熔深增加了1.2 mm,焊缝熔宽增加了1.5 mm。当氮气体积分数为16%时,金属粉末再压缩等离子弧焊接电弧电压平均值为28.47 V,相较于纯氩气时电弧电压平均值增加了0.76 V。与氮气比例为0(即纯氩气)时的标称电弧能量相比,当氮气体积分数为8%和16%时,金属粉末再压缩等离子弧焊接标称电弧能量分别增加了108 W和152 W。当氮气比例为0(即纯氩气)时,金属粉末再压缩等离子弧焊接焊缝上表面显微硬度平均值为180.5HV;当氮气体积分数为8%时,金属粉末再压缩等离子弧焊接焊缝上表面的显微硬度平均值为181.2HV;当氮气体积分数为16%时,金属粉末再压缩等离子弧焊接焊缝上表面的显微硬度平均值为193.3HV。结论在金属粉末再压缩等离子弧焊接过程中,氮气会提高电弧电压和增大标称电弧能量,氮气可以增加焊缝熔深,同时增加焊缝熔宽。当氮气体积分数不大于8%时,对金属粉末再压缩等离子弧焊接焊缝上表面显微硬度平均值基本没有影响;当氮气比例超过一定数值时,才会对金属粉末再压缩等离子弧焊接焊缝上表面显微硬度平均值影响较大。

The work aims to investigate the effects of nitrogen gas proportion on weld formation and hardness in plasma arc welding with additional focusing by metal powder,and guide the plasma arc welding process of 316L stainless steel with addi-tional focusing by metal powder.Firstly,an experimental platform for plasma arc welding with additional focusing by metal powder was set up and improved.Secondly,the impact of nitrogen gas on plasma arc welding with additional focusing by metal powder was focused,and experimental designs were specifically conducted based on different nitrogen gas proportions:in Ex-periment I,the nitrogen gas proportion was 0%;in Experiment II,it was 8%;and in Experiment III,it was 16%.Lastly,welding experiments were carried out,followed by related tests and analyses of the weld joints.When the nitrogen content was 16%,the weld penetration increased by 1.2 mm and the weld width by 1.5 mm compared with pure argon gas welding.With a 16%nitro-gen-argon gas mixture,the average arc voltage of plasma arc welding with additional focusing by metal powder was 28.47 V,with an increase of 0.76 V compared with pure argon gas.Compared with pure argon gas(0%nitrogen),the nominal energy of the welding arc increased by 108 W with an 8%nitrogen-argon mixture,and by 152 W with a 16%nitrogen-argon mixture.With 0%nitrogen(pure argon gas),the average microhardness on the weld surface was 180.5HV;with an 8%nitrogen-argon gas mixture,it was 181.2HV;and with a 16%nitrogen-argon gas mixture,it was 193.3HV.In plasma arc welding with additional focusing by metal powder,nitrogen gas increases arc voltage and nominal arc energy,and enhances weld penetration while also increasing weld width.When the nitrogen proportion does not exceed 8%,there is essentially no impact on the average micro-hardness of the weld surface.However,when the nitrogen proportion exceeds a certain value,it significantly affects the average microhardness of the weld surface.