Possibilities of Stereological Analysis of Grain Boundary Orientation in Longitudinal Sections of Precision Cold Drawn Seamless Steel Tubes

Abstract

Cold drawing of steel tubes refers to a forming operation where a precision steel tube is being formed in a die while reducing tube cross-section, altering the wall thickness and making the final tube much longer than the original hollow. The forming itself takes several drawing passes (a.k.a. draws) depending on the final tube dimension requested. The selection of relative reduction for a particular tube diameter plays an important role because an excessive reduction during drawing causes stresses that induce substantial plastic deformation, eventually leading to cracking. In this paper we evaluate the effect of selected reductions on the longitudinal grain boundary orientation in cold drawn tubes, taking tube sample measurements and making necessary calculations of grain boundary orientation in selected planes.