Abstract: The thermal deformation behavior of 15CrMo alloy steel was investigated through isothermal hot compression tests conducted at temperatures ranging from 900 ℃ to 1 100 ℃, and strain rates ranging from 0.01 s^－1 to 1 s^－1 were examined. The true stress-strain curves of the alloy under high-temperature conditions were obtained, and a modified Hansel-Spittel constitutive model adapted for the rheological behavior of 15CrMo alloy was developed. The relative error of the modified model was only 2.82%. Based on the modified constitutive model, hot processing maps are constructed for strains ranging from 0.1 to0.6. According to these maps, the optimal hot processing temperature range for 15CrMo alloy steel is 900 ℃ to 1 025 ℃, with an optimal strain rate range of 0.01 s^－1 to 0.055 s^－1.

Key words: 15CrMo alloy steel, rheological curve, Hansel-Spittel model, hot processing map