Hot workability of AISI 4140 steel with hot torsion test

A comparative study of the hot workability by hot torsion test of AISI 4140 steel has been carried out. In order to investigate the hot workability of this alloy, different heat treatment conditions have been tested. Hot torsion tests have been carried out on samples of an AISI 4140 steel at strain rates of 1, 1 10 exp -1 and 1 10 exp -2 s exp -1 and deformation temperatures of 850, 925 and 1000 deg C. The effect of heat treatment conditions, deformation temperatures, and strain rates on the workability has been investigated. It was observed that the normalized AISI 4140 steel shows a lower peak stress and a higher strain than oil-quenched and tempered AISI 4140 steel. The best hot workability condition was observed for the normalized AISI 4140 steel.