Cracking and Earing Phenomenon in Deep-Drawn Stainless Steel Alloys: Role of Transformation Kinetics, Microstructure, and Texture

Residual stress, which is a result of interactions between inhomogeneous plastic deformation and microstructure of material, is an important parameter determining deep drawability of stainless steels in terms of delayed cracking. In this study, the correlation of residual stress distributions, martensitic phase transformation, dual phase microstructure, and texture in a series of stainless steel alloys after deep drawing were studied. These stainless steel alloys, which were subjected to deep drawing tests at room temperature, were designed to be metastable austenitic, stable austenitic, metastable duplex, stable duplex stainless steel alloys for providing varied microstructural factors. Macroscopic and microscopic residual stresses induced by deep drawing were measured using split ring tests and synchrotron x-ray diffraction. In addition, synchrotron x-ray diffraction was carried out to obtain the strain-induced α’ martensite phase fraction and texture of constituent phases around the tips of deep-drawn cups. The effects of martensitic phase transformation and ferrite phase on residual stress partitioning and austenite texture evolution after deep drawing are discussed, and this study can give a basic understanding of delayed cracking behavior of stainless steels.