Plastické vlastnosti křemíkové transformátorové oceli za tepla

Abstract

This bachelor thesis examines the hot plastic properties of silicon transformer steel using uniaxial tensile tests, for the first time on the HDS-20 simulator in Ostrava with flat samples, because the supplied strip cutting of 2.4 mm thickness did not allow the production of traditional circular cross-section samples. Trends of plastic properties in the temperature range of 800 – 1400 °C have been obtained by analyzing the stroke diagrams and measuring the dimensions of fracture surfaces. Strength of the tested steel decreases monotonously with increasing temperature. The maximum of ductility and contraction are located near 1200 °C, the temperature of zero ductility came out slightly above 1400 °C. A new methodology for hot tensile testing of flat samples has been mastered, but temperature control has also been shown to be much less accurate in this case than in the course of testing the traditional circular cross-section samples, resulting in a significant variance of results.