Precipitation of Copper Sulfide and its effect on the Microstructure and Properties of Steel

The precipitation behavior of copper sulfides in strip cast and isothermal heat treated low carbon steel were investigated by SEM and TEM. The copper sulfides were classified as duplex inclusion of oxide and sulfide (OS), plate-like copper sulfide (PS), shell-like copper sulfide (SS), and nano-scale copper sulfide (NS). Based on the experimental results, the formation mechanisms of these copper sulfides, as well as the effects of cooling rate and constituentes of steel on the competitive precipitation between copper sulfide and manganese sulfide were discussed. The effects of coppers sulfides on the mechanical properties as well as the formation of acicular ferrite in steel were also introduced.