Reduction of Residual Stresses in Cold Drawn Pearlitic Steel by a Soft Secondary Wire Diameter Reduction

In this paper, the effects of the skin pass technique on the residual stress and plastic strain fields generated in cold drawn pearlitic steel wires are analyzed. The aim is to find out the optimal conditions to be used in the design of a manufacturing process for obtaining more reliable structural components in terms of the main cause of failure: the hydrogen embrittlement (HE). To achieve this goal, diverse numerical simulations were performed by using finite elements (FE) and considering, on one hand, the first step of a real cold drawing chain, using (i) a conventional drawing die and (ii) modified drawing dies with different soft diameter reductions, and, on the other hand, numerical simulations by FE of the hydrogen diffusion assisted by stress and strain states to estimate the hydrogen distributions. Obtained results revealed the secondary reduction degree as a key parameter in the die design for reducing the drawing-induced residual stress. According to the results, low values of the reduction ratio cause radial distributions of residual stress with significant reductions at both the wire core and at the wire surface. In addition, the hydrogen accumulation at the prospective damage zone (near the wire surface) given by FE simulations is lower in the wires drawn with modified drawing dies including a skin pass zone.

Automated summary

The effects of the skin pass technique on the residual stress and plastic strain fields in cold drawn pearlitic steel wires are analyzed in this study. The goal is to find optimal conditions for manufacturing more reliable structural components by reducing the main cause of failure, hydrogen embrittlement. Numerical simulations using finite elements and considering different drawing dies and reduction ratios were performed to estimate the hydrogen distributions. Results showed that the reduction ratio is a key parameter in reducing the drawing-induced residual stress, and the use of modified drawing dies with a skin pass zone can lead to lower hydrogen accumulation in the prospective damage zone.