Development of electrode used for X80 pipeline steel on production line

A kind of electrode with low hydrogen used for X80 pipeline steel on production line was developed and applied for the backing and repair welding of X80 pipeline steel.The proper proportions of the electrode components were determined, and a series of welding experiments and subsequent test for microstructure and mechanical properties of welded joints were carried out.The results show that with the developed electrode,the arc ignition and arc stability was good,little spatter happened, the welding slag was easy to remove and the weld appearance was excellent.The mechanical properties of joint made with B electrode were superior with the yield strength up to 640 MPa,tensile strength 804 MPa and impact energy value 120 J.The microstructure of the weld metal with B electrode consisted of acicular ferrite and granular bainite with appropriate proportion and matched well with parent material.