Behaviour of Surface Defects in Wire Rod Rolling

Abstract

Defects are often present in rolled products, such as wire rod. The market demand for wire rod without any defects has increased. In the final wire rod products, defects originating from steel making, casting, pre‐rolling of billets and during wire rod rolling can appear. In this work, artificial V‐shaped longitudinal surface cracks have been analysed experimentally and by means of FEM. The results indicate that the experiments and FEM calculations show the same tendency except in two cases, where instability due to fairly “round” false round bars disturbed the experiment. FE studies in combination with practical experiments are necessary in order to understand the behaviour of the material flows in the groove and to explain whether the crack will open up as a V‐shape or if it will be closed as an I‐shape.

A Study of Surface Deformation during Wire‐Rod Rolling of High Speed Steels using Experimental and Computational Techniques

“…The assumptions were that the welds deform as the surface layer of the base material and that they also deform in the same way as open cracks. The latter assumption can be supported by simulations by Fil- ipovic [12], as described previously. Thus, it is assumed that the evolution of weld and crack depths are similar.…”

“…Monid found that changing from box grooves to diamond/square grooves decreased the maximum depth of the decarburized layer with 15-30 % and its depth variation C~el = d i . fA;; I do VA; (2) [12] investigated the evolution of surface defects during wire-rod rolling both experimentally, by rolling short bars with machined longitudinal V-shaped groves positioned at three different sites along the periphery of a round bar, and theoretically by simulating the experimental setup for cracked and for defect-free bars using FEM. When the simulations were compared with experimental work, it was found that the cracks reduced in size faster in experiments than in simulations.…”

Experimental and numerical studies on flow behavior of surface defects in the heavy rail rolling

“…In heavy rail rolling, continuous casting slab is heated above its temperature of recrystallization and passed through several grooves in the rolling mill (Filipovic et al , 2006). Surface defects such as longitudinal surface cracks or transverse surface cracks of hot rolled steels are potentially serious problems during the rolling process because these might severely affect the quality of the rolled products, and might result in rejection of the rolled materials and mill stoppage (Yu et al , 2013).…”

“…Wang et al (2015) investigated the evolution of V-shaped surface transverse cracks with different depths during reversing rolling process of medium plates using 2D FEM. Filipovic et al (2006) studied opening and closing of artificial V-shaped longitudinal surface cracks in wire rod rolling by experiment and MSC MARC software to eliminate the cracks or minimize their negative influence. Yu et al (2009), Yu et al (2008), Yu et al (2006) and Yu and Liu (2009) simulated the behavior of transversal and longitudinal cracks on the slab surface during the vertical–horizontal rolling process by finite element software LS-DYNA, and the influences of the crack size, crack open-angles, the maximum compressive and tensile stress at crack tip, temperature and contact pressure on crack surface, the edger roll shape, the friction coefficient and the fillet radius of grooved edger roll on the closure and growth of cracks were analyzed.…”

Three-dimensional metal particle flow simulation during the whole rolling process for 60 kg/m heavy rail

“…The market demand for heavy rail without any defects has increased. [2][3][4] Therefore, understanding the metal flow behavior in the process of heavy rail rolling becomes very important. Heavy rail rolling has characteristics of a lot of rolling passes and section grooves, complex cross-sectional shape, large velocity, difference of roll, and concurrence of direct pressure and lateral pressure in groove.…”