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 °C, finishing temperature = 837 °C and coiling temperature = 580 °C. The predicted
values were close to the experimental values, indicating the suitability of the
models.