Influence of the heat treatment on the mechanical properties and structure of TWIP steel in wires

Abstract

Purpose: The aim of this paper is to determine influence of the drawing process of TWIP steel wires on their mechanical properties and the structure changes. Design/methodology/approach: The heat treatment of steel containing 29.4 % manganese and little amount of carbon (0.0049%C) allows to obtain TWIP effect, and the austenitic structure for this type of steel was realized. In order to investigate the structure changes, the optical microscopy was used. Mechanical properties were determined by the compression test and drawing process. Findings: The analyses of changes of mechanical properties and the structure after particular drawings stages was carried out. At the total draft of 93.4 % the value of drawing stress was 1060MPa, however further deformations of the wire brought relation Rm/R0.2 to be above 1.6. Research limitations/implications: Continuation of the investigations with the use of transmission electron microscopy makes it possible to identify all phases that appear in this steel. Practical implications: Drawn products characterized by high strength properties together with good plasticity might be used for production of connecting elements because they can absorb large quantity of energy. Originality/value: For the first time there were obtained so high hardening level as well as so high plasticity in the drawing process.