Splitting of pipe steel produced by TMCP

Abstract

The texture of low-carbon low-alloy pipe steel sheet with bainitic structure produced by thermomechanical controlled processing (TMCP) is studied by means of electron backscatter diffraction (EBSD). Samples generally characterized by splitting (secondary cracks) on fracture in mechanical tests are compared with those that are free of splitting. Splitting occurs in the presence of regions that consist of small crystallites with uniform (001)[110] orientation; those regions extend in the direction of controlled hot rolling. The formation of such regions is thought to be due to γ → α shear transformations with different treatment parameters.