Influence of Backing Plate on the Mechanical Property of Weld Metal in Full Penetration Joints

Abstract

The base materials used were TMCP385B and SA440B with a plate thickness of 40 mm. For the backing plate, a SN490B blast-furnace steel sheet with a thickness of 9 mm and two types of electric furnace steel plates with different nitrogen contents were used; a blastfurnace steel plate stock was also used for comparison. JIS Z 3312 G59JA1UC3M1T was used as the welding wire. MAG welding was used as the welding method. It was determined that the material of the electric furnace steel sheet, i.e., SN490B, which is the current backing-plate material, did not cause any deterioration in the quality of the weld metal properties. This behavior is attributed to the formation of intragranular ferrites by Ti oxide.