An elevated temperature damage model for 45Cr4NiMoV steel heavy backup rollers

Abstract

Crack defects of material during hot forging processes cannot be accurately predicted using the current finite element (FE) codes. One of the main reasons for this is that mechanisms of material damage in hot metal forming processes are dependent on temperature and strain rate. Heavy backup rollers are a key part of rolling production lines. To effectively predict internal fracture of heavy backup rollers in hot forming processes, an elevated temperature damage model based on Cockcroft-Latham criterion was proposed to account the influence of elevated temperature and strain rate. Tensile tests of 45Cr4NiMoV steel for heavy backup rollers were implemented by a Gleeble-1500D thermal-mechanical simulator from 700 °C to 1150 °C and at three strain rates (0.01 s−1, 0.1 s−1, 1 s−1); this led to identification of material parameters of the proposed damage model. Finally, the developed damage model was integrated into commercial FE code FORGE, As well as the simulations of tensile tests at elevated temperature were conducted to validate its accuracy. The results show that the new damage model is able to predict crack defects in hot forging processes for 45Cr4NiMoV steel heavy backup rollers.