Hot deformation behaviour and Hansel-Spittel constitutive model of Cr5 alloy for heavy backup roll

The heavy backup roll is a key component in large steel rolling production line, as it supports the work roll to prevent any excessive deflection. The backup rolls are traditionally produced by large-scale forging process. To accurately describe the high temperature flow behaviour of a newly developed roll material Cr5 alloy for numerical forging simulation, a thermal simulation testing machine, Gleeble-1500D, is used in this work. The isothermal compression experiments are carried out to study the flow behaviour of Cr5 alloy at temperature range of 900 to 1,200°C, and strain rate range of 0.005/s to 5/s. Hansel-Spittel model is thus used to establish the constitutive equation of the material under hot deformation. The accuracy of the constitutive equation is analysed by using correlation coefficient r. The validation shows that this equation can accurately predict the thermal deformation behaviour Cr5 alloy. The Hansel-Spittel model is implemented into the Forge software, and the FE simulation of a compression process is compared favourably with the experimental data.