Development of High Strength Batch Annealed Low Carbon Steel for Automotive Application
In order to increase the strength and formability of batch annealed sheet steels, design of experiment method was used to set up an experimental matrix with five factors, including C, Mn, P in steels, coiling, and batch annealing temperatures, at two levels. Effects of these factors were analyzed using analysis of variance and linear regression methods for cold spot and hot spot, respectively. Linear regression results showed that higher alloying element contents and coiling temperature will increase strength and deteriorate elongation, which is opposite to the effect of annealing temperature. Analysis of variance showed similar results to those of linear regression, except the effect of C on elongation and effect of coiling temperature on tensile strength and elongation are negligible for cold spot. For hot spot, effect of coiling temperature on tensile strength is small.