Study on model of metal structure refinement during hot deformation

A theoretical equation of deformation work, temperature of phase transformation, initial grain size and metal structure is given in this paper. The theoretical values are similar to the experimental values for steel Q235. On this basis, studies on steel Q235 were investigated. It is shown that the ferrite grain size decreases smoothly from 4.56 μm in the center to 2.93 μm at the edge with sheet of 2.5 mm thickness, with a heating temperature of 950 °C, a holding time of 5 min and a reduction of 40%. The average grain size is 3.74 μm.