Analysis of the deep drawing behavior of 2507 super duplex stainless steel based on texture and microstructure evolutions

Abstract

Tensile tests and deep drawing under different drawing ratios were carried out on 2507 duplex stainless steel (DSS). The effects of the microstructure and microtexture on the formability of the as-received sheets were examined by optical microscope and electron backscatter diffraction. Deformation microstructures in different regions of the drawn cup were also analyzed with transmission electron microscopy. The results indicated that 2507 DSS sheet had serious anisotropy and obvious 45° ears. Textures of the as-received sheet showed that the strong α-fiber texture in the ferrite (α) was dominant, while the texture intensity in the austenite (γ) was weak. The {001}<110> and {112}<110> orientations were the main factor that resulted in the low Lankford parameter (r-value) and high planar anisotropy (Δr). The microstructures in different regions of the drawn cup showed that the different crystal structure of α and γ phases led to the inhomogeneous strain distribution. The decrease of the deep drawability was attributed to the incoordinate deformation between the α and γ phase.