Response surface methodology to predict the mechanical properties of hot-rolled sheets

The goal of this study is to empirically investigate the major hot rolling process parameters affecting the yield strength, ultimate tensile strength and strain-hardening exponent of Nb-microalloyed steel sheets. The parameters considered were the roughing, finishing and coiling temperatures. Three levels for each parameter were used to develop a model relating the process parameters to mechanical properties. By applying the response surface methodology, analysis of variance was done to determine the mathematical models related to each response. The results indicated that decreasing the coiling and finishing temperatures significantly influenced the mechanical properties. Also, the models predicted that the maximum yield strength, ultimate tensile strength and strain-hardening exponent are simultaneously obtained under the following conditions: roughing temperature = 1097 degrees C, finishing temperature = 837 degrees C and coiling temperature = 580 degrees C. The predicted values were close to the experimental values, indicating the suitability of the models.