Temperature-displacement simulation of shape metal 9-pass-cogging process

Abstract

In order to study the stress, strain and temperature field during the cogging of shape-metal hot rolling, the H-beam 9-pass-cogging process was simulated use ABAQUS6.5 (License Agreement Identifier: 27SHANU). The material stress-strain cures under different plastic strain rate at a temperature range from 800 to 1300 Celsius were studied use the Gleeble1500 thermo-mechanical tester. The 9-pass-cogging process involves passing heated stock through nine different calibres until the desired cross-sectional shape was achieved. Without elements re-mesh, the whole process couldn't be simulated successfully since the excessive element deformation. So a brick element re-meshing technique based on the characters of the H-beam rolling process was presented, which was turned to be very suit for the so-called uni-directional forming, such as metal extrusion and complex shape metal hot rolling. The re-meshing approach consists of the following steps: First, steady state criteria were specified to halt the simulation when rolling process achieving a steady-state condition; Second, nodes on the steady-state element set were extracted and projected to create a two-dimensional plane, and then transient thermal analysis modelling the stock cooling process during the 30 seconds between the roll passes was performed; Third, a finer mesh model was generated, and a heat transfer analysis using sub-modelling technique was used to transform nodes temperature. Finally, a three-dimensional model was constructed, and the nodes temperature and effective plastic strain were transformed from inter-pass transient thermal model and coupled temperature displacement model respectively. The effectiveness of re-meshing technique was proved in the ABAQUS6.5 by the 9-pass-cogging simulation of H-beam hot rolling. The detailed results of the stress and temperature filed were got.