Experimental investigation and simulation of structure and tensile properties of Tempcore treated rebar

• We develop a mathematical model for simulating the Tempcore process.
• The model consists of three parts, thermal model, metallurgical model and mechanical model.
• The model has been applied to B500B steel bars. Its variables are expressed in terms of chemical composition, and process parameters, namely: bar diameter, rolling temperature, number and setting of cooling nozzles, cooling water flow rate and quenching time.
• It is found that numerically calculated data are in good agreement with those obtained from experimental trials accomplished at EZZ STEEL plant.

This paper presents a mathematical model for simulating Tempcore process, the model consisting of three successive parts. Thermal model is used to predict the temperature distribution across the bar over its whole quenching and self-tempering rout. The output of this model is used to calculate the area of martensite formed in outer layer and ferrite–pearlite heart. The composite rule of mixtures (ROM) is used to correlate the tensile yield strength of the bar with the martensite and ferrite–pearlite volume fraction. The model is capable of predicting the effect of various process parameters namely; bar diameter, rolling temperature, number and setting of cooling nozzles, cooling water flow rate and quenching time on the thermal conditions across the bar during different stages of the process, structure formed and tensile behavior of the rebar. A good agreement is found between the predicted results and the experimental data for B500B steel with diameters from 10 to 16 mm and yield strength varied from 400 MPa to 700 MPa.

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