Effect of Intermetallic Compounds and Inclusions in Normalizing Rolled C–Mn Steel Plate Butt Joint Failure

Abstract

Production weld tests were usually conducted in steel fabrication industries to ascertain the process reliability and product quality. Plate groove butt joint test specimens, prepared from production weld test coupon, were failed during the mechanical test. To analyse the root cause for joint failure, a series of tests were conducted on prepared samples from production weld test. The macro-examination was conducted at the failed region, and microstructure analysis was carried out by optical microscopy and scanning electron microscopy on the banded structure of the base metal and at heat-affected zone. The purpose of this investigation is to identify the effect of the non-metallic inclusions in the segregated banded zone during welding of plate butt joint and to identify the impurity elements responsible for the weld failure. From this investigation, it was found that the presence of manganese sulphide, lead sulphide and aluminium oxides in the segregated zone decreased the mechanical properties of the plate groove butt joint weld in terms of failure.