New model describing the hot stress-strain curves of HSLA steel at high deformation

The torsion test is often applied for the determination of the hot flow stress of steels. An originally derived system of equations has been used to describe the basic parameters of the torsion test and has enabled precision to be obtained in the simulation of flat rolling. Because of the relatively low strain rates obtained with a torsion plastometer, it is necessary to extrapolate the laboratory results into the range of real working conditions. In this case, only a limited number of demanding and expensive interrupted tests have to be done. The more important role is then played by computer prediction based on equations that incorporate the results of simple, but mainly continuous tests. Examples of such mathematical models are presented, including the influence of dynamic or static softening in hot rolling.