The sulfide inclusions in the steel plate are distributed in the form of sheets along the rolling direction, which is the origin of ductile tearing, which reduces the toughness and resistance to lamellar tearing of steel. Sulfur in steel is harmful to hot working and welding. It forms FeS with iron and easily forms eutectic with low melting point (the melting point of eutectic Fe-FeS is 985℃). The eutectic melts during hot processing (1000-1200°C), causing the steel to crack at high temperatures. This phenomenon is called "hot brittleness". At high welding temperatures, FeS and molten iron can be infinitely miscible. When the molten pool solidifies, FeS forms a low-melting eutectic with Fe or FeO, which may cause crystalline cracks in the weld.