In recent years, the steel structure industry began to use welding ceramic liner from the root process, it is a kind of weld groove opposite after laying welding ceramic liner for welding on the front and reverse side weld force forming, make the full weld, weld neat welding method.Its advantages are:2, the appearance quality.Traditional opposite gouging clear root welding technology determines the weld double-sided are manual welding, so the appearance quality of the weld quality depends on the level of operating skills.While the ceramic liner from the root process, because the ceramic liner itself to assist the formation of welding molten pool, and force the molten metal according to the shape of ceramic liner weld formation, the opposite of contact with the ceramic liner weld appearance beautiful smooth, without defects, weld size and the weld residual high size stability.� optimized (appropriate increase welding current, etc.) of the roots of the welding penetration, finally after ultrasonic testing of the weld specimen, X-ray detection and weld mechanical properties testing, found no clear effect of root process to the traditional process, meet the requirements of production of van.