FEM Comparative Between Two Roller Sizes for Hot Shape Rolling of Reinforcement Bars Fabrication

Hot rolling of reinforcement bars (rebars) is a common industrial process, which has been largely studied. Most rebars are rolled from low carbon steel billets. However, there is an increasing tendency to roll these products from recycled steel rails. Steel rails are made of eutectoid steel and after several years of use their geometry is very irregular. These irregularities along with the relatively stronger eutectoid steel makes rolling more demanding. This paper presents the results of finite element modeling of the hot rolling passes for rebar fabrication from recycled eutectoid steel rails. The fully-coupled model was developed using DEFORM-3D and takes into account the heat transfer equations, strain tensor and boundary conditions such as friction and heat transfer coefficient. A parametric study was carried out in order to assess the effect of geometry irregularities in the rolling pass efficiency. Model validation was carried out by in-plant measurements. The results are discussed in terms of throughput and shape of the final product, as well as in the calculated stresses in the rollers. Finally some suggestions regarding improvements of the rollers to increase productivity are presented.