DEVELOPMENT OF A NEW LOW-CARBON LOW-ALLOY STEEL SUITED TO BE CLAD WITH STAINLESS-STEEL

A new steel containing low C and low Nb, Ti and N has been developed which is suited to be clad with austenitic stainless steel. The steel should have fine ferrite grains in the final stage in order to avoid an orange peel phenomenon in its subsequent plastic deformation. Various parameters affecting the resultant ferrite grain size of the steel have been investigated. Main factors favored to obtain fine ferrite grains are (1) Ti/N in atomic percent being 0.5 rather than 1.5, (2) high Nb and C contents for the steel annealed in gamma-region, (3) annealing of the steel in alpha-region rather than in gamma-region, (4) the faster cooling rate after the final annealing process. In accordance with these results, three possible ways to make steel having grains finer than 7 in JIS grain size number are proposed, and finaly a low C, low Nb, Ti and N steels have been successfully clad with austenitic stainless steel on mill and laboratory scales which has shown no orange peel phenomenon in their subsequent plastic formings.