Constitutive Relation of Alloy Steels at High Temperatures

초록

This paper presents a feasibility study whether Shida’s constitutive equation being widely used for plain carbon steel in steel manufacturing industry can be extended to alloy steels with a due carbon equivalent model. The constitutive relation of the alloy steels (SAE9254, AISI52100 and AISI4140) is measured using hot deformation simulator (GLEEBLE 3500C) at high temperatures (800oC ~1000oC) within strain rates of 0.05~40 s-1. It has been found the predicted flow stress behavior (constitutive relation) of AISI52100 steel is in agreement with the measured one. On the other hand, the measured flow stress behavior of SAE9254 and AISI4140 steel partly concords with the predicted one when material experiences relatively high strain rate (10~40 s-1) deformation at low temperature (800oC). It can be deduced that, for AISI52100 steel, Shida’s equation with the carbon equivalent model can be applicable directly to the roughing and intermediate finishing stand in hot rolling process for calculating the roll force and torque.

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