Vlastnosti tyčové oceli tažené z tepelně zpracovaných tyčí a svitků

Abstract

Current technological trends are often described by increasing demands on the high strength material and high impact strength of steel drawn bars. For increasing of these characteristics is of ten necessary to carry out heat treatment. For these reasons is company Trinecke Zelezarny, a.s. trying to extend product portfolio of heat-treated drawn rod, especially quenched and tempered drawn bars. Quenching and tempering provils good relation between tensile strength, elongation and impact strength. As during drawing proces increases strength and decreases toughness, is itnecessary to optimise parameters of quenching and tempering to achieve requested mechanical properties after drawing. This thesis deals with theory of steel drawing and mechanical and structural properties of drawn steel 42CrMo4. In the thesis isdescribed strength, hardness, impact strength and microstructure of steel after hot-rolling, annealing and drawing and compares the results. In experimental part were optimise parameters of heat treatment to achieve demanded properties.