Optimizing Process Parameters Using RSM to Increase the Strength and Ductility of B500BWR TMT Rebar

This study investigates the influence of hot working process parameters on the mechanical properties of thermomechanically treated (TMT) rebar grade B500BWR. The process involves hot rolling followed by quenching and self‐tempering. The goal is to identify the optimal parameter settings for achieving the desirable tensile strength, yield strength, and ductility. A central composite design which is a statistical technique within the response surface methodology (RSM) framework is employed to optimize the process. The investigated parameters include intermediate temperature (900°C–1000°C), water pressure during quenching (1.1–1.31 MPa), carbon content (0.18%–0.21%), and carbon equivalent (0.31%–0.33%). Mathematical models are developed to predict the ultimate tensile strength, yield strength, and elongation based on the process parameters. Statistical analysis confirms the models′ high significance through R ‐squared values of 0.965, 0.935, and 0.9434 for yield strength, ultimate tensile strength, and elongation, respectively. The results reveal that the intermediate temperature and water pressure have the most significant influence among the investigated parameters. The predicted optimal settings are 910.13°C for intermediate temperature, 1.3 MPa for water pressure, 0.2029% for carbon content, and 0.3233% for carbon equivalent. These settings are predicted to yield the rebar with an ultimate tensile strength of 660 MPa, yield strength of 581 MPa, and elongation of 23%. This study demonstrates the effectiveness of RSM in optimizing the TMT rebar production process to achieve the desired mechanical properties. The identified optimal parameters can be used to guide the manufacturing of B500BWR rebar for enhanced performance.