An investigation of tearing failure in fine-blanking process using coupled thermo-mechanical method

In fine-blanking processes, localized deformation is prone to cause tearing failure at the surface of shearing edges, which can influence the quality and functionality of the blanked part. In this paper, a numerical simulation of a fine-blanking process has been conducted by using a coupled thermo-mechanical finite element method. The thermal effect on the material properties has been taken into account in the simulation. On the basis of the results of the simulation, the distributions of equivalent plastic strain and stresses in a fine-blanking process have been analyzed. Moreover, examinations of metallurgical microstructure by means of optical and scanning electron microscopy have been performed. It has been observed that the grains near the shearing edge were highly distorted within a narrow shearing zone. The formation of microvoids under large shear deformation supports the argument that material damage initiates and develops around this local area during the fine-blanking process. It is suggested that tearing failure could initiate from the damaged area of the workpiece adjacent to the tool tips where cracking occurs due to excessive local tensile stress produced by fine blanking attributes and interfacial friction.Department of Industrial and Systems Engineerin