Vliv složení válcovaného drátu a technologie výroby na finální vlastnosti pneudrátu

Abstract

Diploma thesis deals with effects of chemical composition of steels and production technology on final properties of cord-wires. In the theoretical part key properties of wires and quality requirements on rolled semi-products are discussed. Furthermore, technology of cord–wire production and methods of evaluation of input and output products are described. Diploma thesis deals with cord–wires manufactured from five casts of nearly identical chemical composition. As-rolled wires were de-scaled either mechanically or chemically, or were heat treated by austempering. Conditions of drawing and the next processing of wires were identical. Based on alternate bend test results it was found out, that the worst results were achieved in the case of mechanical de-scaling. Drawn wires from one cast did not comply with the required number of bends (11). Characterization of broken wires from casts investigated included fractography, investigations on surface morphology of wires, microstructure analysis and microhardness evaluation. Based on the results, a revision of the mechanical de-scaling process in the KERN s.r.o. company was recommended, which should be focused on measures which could lead to the surface quality improvement of de-scaled as-rolled wires.