Some mechanical and magnetic properties of cold rolled X5CrNi 18-8 stainless steel

Abstract

Purpose: The paper analyzes the influence of the degree of cold deformation on the structure forming and changes of mechanical and magnetic properties of cold-rolled sheet on austenitic X5CrNi18-8 stainless steel. Design/methodology/approach: The investigations included observations of the structure on a light microscope, researches of mechanical properties in a static tensile test, microhardness measurements made by Vickers’s method and magnetic behaviors determine by used normalized non-destructive testing methods (NDT). The analysis of the phase composition was carried out on the basis of X-ray researches. In the qualitative X-ray analysis the comparative method was applied. Whereas X-ray quantitative phase analysis was carried out by the Averbach Cohen method. Research limitations/implications: The X-ray phase analysis in particular permitted to disclose and identify the main phases on the structure of the investigated steel after its deformation within the range 10%-70%. Moreover results of the X-ray quantitative analysis allowed to determine the proportional part of martensite phases α` in the structure of investigated steel in the examined range of cold plastic deformation. Practical implications: The analysis of the obtained results permits to state that the degree of deformation has a significant influence on the structure, mechanical and magnetic properties of the investigated steel. Besides, it was found that the plastic deformation in cold rolling process of metastable austenitic steel type X5CrNi18-8 induces in its structure a phase transformation paramagnetic austenite into ferromagnetic martensite. Originality/value: plastic deformation in cold rolling process in the austenitic X5CrNi18-8 stainless steel a good correlation was found between changes of the structure and the effects of investigations of the mechanical properties, connected with martensitic α’ phases forming. Existing this relation is of essential practical importance for the technology of sheet-metal rolling of austenitic steel.