Finite element modelling of the effect of non-metallic inclusions in metal forming processes

The presence of non-metallic inclusions can result in material failure during the metal forming process, or lead to a serious deterioration of the quality of the final product. Understanding the effects of inclusions during metal forming is therefore an important step towards predicting the behaviour of inclusions and subsequently minimising their consequences. To achieve this understanding the authors incorporated non-metallic inclusions into a finite element (FE) simulation of metal forming. The chosen metal forming process was rod drawing, the chosen inclusion material aluminium oxide (Al 2 O 3 ) and the chosen inclusion shape spherical. Real rod drawing experiments were also designed with Al 2 O 3 spheres embedded in a steel rod in order to compare experimental and simulated results. Specifically, from the experiments carried out the changes of the rod around the inclusion were investigated and the findings compared with the finite element simulation results of an equivalent model. The FE simulation of the experiments considered specifically the fracturing of brittle inclusions. A concept allowing the fracturing of brittle inclusions by means of finite element method is described. Experimental results from fourpoint bending tests, and tensile tests, for Al 2 O 3 ceramic bodies were used to calibrate the simulation. Further experiments involved the crushing of Al 2 O 3 spheres where the force necessary to achieve crushing was measured and compared with the results of the calibrated FE simulation, It is demonstrated that the intended FE method for the simulation of brittle fracture of inclusions can be used with good accuracy.