Možnosti snížení obsahu dusíku u rychlořezných ocelí a jeho vliv na obsah zbytkového austenitu

Abstract

This diploma thesis focuses on the nitrogen content in high-speed steels (HSS) and its influence on their structure and mechanical properties, particularly the amount of retained austenite. The theoretical part describes the characteristics of HSS, their chemical composition, production methods, and the effect of nitrogen on the microstructure. Special attention is given to nitrogen solubility in the melt, mechanisms of its absorption, and reduction methods during production. The experimental part compares four melting approaches: vacuum melting under laboratory conditions at VSB, conventional melting in two induction furnaces with prolonged exposure to high temperatures, controlled melting in a single induction furnace minimizing metal-atmosphere contact, and melting from a clean charge. The results will be evaluated in terms of nitrogen content and its impact on the final structure and properties. The aim is to propose an optimized melting process with minimal risk of nitrogen oversaturation and improved performance of HSS.