Investigation on the High-speed Precision Shearing of 5140 Steel Bars Pre-grooved by Laser

Abstract

A new blanking method is proposed to improve the quality of metal bars, by introducing the laser pre-grooving and high-speed precision shearing technology. The working principle is introduced, and the calculation method of the laser groove depth is given. By means of finite element method, the elastic-plastic deforming, damage initiation and crack propagation behaviour of a 5140 steel bar under high-speed shearing are obtained; furthermore, the corresponded shear force-displacement property is analysed in detail. After that, high speed shearing experiments are done of laser grooved 5140 steel bars. The results show that the 5140 steel bar undergoes rapid elastic and little plastic deformation before crack, and micro cracks initially appears in the lateral area with the damage value of 0.53; then main vertical cracks form and extend along the shearing direction; the fracture section of the billet is flat and smooth, with a section inclination of 0.3°and a weight tolerance of 0.35%.