Evaluating Residual Stress Profile in Cold Drawn 1018 Steel Rods Using Finite Element Analysis

Abstract This work explores a finite element (FE) method-based residual stress profile estimation technique for cold-drawn steel rods. The surface contour method is a well-known technique in which displacement normal to the lateral cut is used in the FE model to estimate residual stress. However, the lateral cut can affect residual stress, leading to errors in estimation. In this work, the samples were cut axially at different locations throughout the thickness, and the warp on the samples was measured and matched using FE analysis. Two categories of samples were prepared from the same rectangular cold-drawn steel bar: (i) samples with only top surface cut of different depths and (ii) samples with EDM cuts at different positions through the thickness. A three-step finite element analysis was carried out to model stress relief due to cutting. The deflection was compared with experiments, and several stress distribution profiles were developed until a best-matched residual stress was found. A residual stress profile of tension-compression-tension showed the best match for the surface-cut samples. The residual stress profile was further modified to no stress in the middle region to match the EDM cut deflections. This shows that the profile can be estimated using the approach presented here. The advantage of this approach is that the deflection over the length can be used for optimization, which will allow us to obtain unique solutions to the stress profile.