The effect of thermomechanical treatment on residual stress level of A53 steel pipe

Abstract

Residual stresses often become the cause of early damage to equipment or machinery. Residual stress generally appears on components as a result of improper equipment design and improper of manufacturing processes. Cold working processes on metals can provide plastic deformation. Plastic deformation that occurs will cause lattice distortion on the metal structure. This lattice distortion will cause residual stress. Greater the degree of cold working on the metal, greater the residual stress level in the metal. In this research, measurement of residual stress was carried out on as received specimen and treated specimens. The treatment given is cold work by rolling and thermomechanical treatment (cold work + normalizing). Residual stress measurement is carried out using the hole drilling method. The results show that when the deformation percentage is higher, the residual stress will be higher as well. One of the methods to relieve residual stresses in material is by heat treatment process. In this process, the residual stress on material will decrease significantly accompanied by changes in the microstructure inside the metal. However, if the application of the heat treatment process is not right, besides experiencing a decrease in residual stress, the metal will also experience decreasing in strength and therefore proper treatment process is needed through understanding the phenomena that occur during the process of heat treatment of metals that have high residual stress. For this reason, a detailed understanding about the effect of thermomechanical treatment on the residual stress level is important to investigate.