通过采用氩气分析仪对不锈钢、马氏体钢等高合金钢在焊接过程中充氩的浓度大小进行测定，讨论氩气浓度的大小对不锈钢、马氏体钢等高合金钢焊缝内部质量的影响。试验表明：氩气浓度的大小对焊缝根部的保护效果有很大的影响，管道内部氩气浓度是制约焊缝内部质量的关键，是保障焊接质量的重要环节。

In the paper,the argon concentrations are measured by argon gas analyzer during the weldings of high alloy steel,such as stainless steel,martensite steel and etc,of which the effect on weld internal quality is discussed.It is shown from the experiments that the argon concentration in the pipes has significant effect on root protection of weld,which is critical to welding quality.