Automatic Welding Technology Of Small-Diameter Round Steel Pipe By TIG Welding

In many manufacturing enterprises, it is generally prevalent that technical workers weldsmall-diameter round steel pipe by utilizing manual tungsten electrode argon arc weldingmachine, but it is inefficient and with little success. Welding this kind of pipe could beaccomplished automatically by using [TQK00600]TIG welding machine, so that productioncost can be reduced and quality of products can be satisfactory. The experiments areperformed on low alloy steel16Mn. This paper includes optimization of welding parameters,welding joint organizational analysis, tension test and bending test.When workers weld small-diameter round steel pipe by using welding parameters whichare adopted by experience, the test result indicates that weld pool will not be formed ifbacking welding current is less than90A. Selecting a reasonable welding current andconnecting clearance is crucial in backing welding.Metallographic structure of welding joint indicates that ferrite distribution is uniform, ifwelding this kind of pipe with the clearance of1.0mm. The metallographic structure issatisfactory. In the welding joint, the overheated zone of1.0mm is narrower than1.5mm,which can reduce the probability of structural failure.The result of mechanical property test shows that welding joint tensile strength andpercentage of elongation of1.0mm and110A is greater than1.5mm. This test result indicatesthat the product with the clearance of1.0mm is superior to1.5mm. In the bending test,samples of different connecting clearance are not cracked and cracks are not found. It can besure that toughness of joint is suitable.The quality of product is suitable when welding small-diameter round steel pipe in thematerial of low alloy steel16Mn, by using welding current of110A and the connectingclearance of1.0mm. The percent of pass come up to95percent by using [TQK00600]TIG...