The effect of grain refinement on the mechanical properties of a micro alloyed steel

High strength low alloy steel was produced by electric arc furnace, vacuum degassing, ladle treatment and continuous casting route. The steel was hot rolled by applying a schedule to simulate industrial control of hot rolling procedure for the production of plates as closely as possible in laboratory level, in order to investigate the effect of applying different strain rates onto hot rolling procedure in the range of temperatures between 1250 to 900oC. After the hot rolling procedure, the plate was spray cooled at a cooling rate of 5oC/s to a temperature of 650oC and then cooled to room temperature. The results showed a grain refinement as a function of the strain rate increases from 1 to 8 s-1 and as a consequence an increase in mechanical properties of: yield strength and ultimate tensile strength; and keeping almost constant the ductility.