Microstructure of austenitic stainless steel is primarily monophasic, i.e. austenitic. However, precipitation of the δ-ferrite in the austenite matrix is possible depending on the chemical composition of steel. δ-Ferrite is stable on room temperature but it transforms into σ-phase, carbides and austenite during heat treatment. In this work, the results of analysis of influence of temperature and time on decomposition of δ-ferrite are presented. Magnetic induction method, microstructure and hardness analyses were used for testing the degree of decomposition of the δ-ferrite. Analysis of results showed that increase in temperature and time increases the degree of decomposition of δ-ferrite.
In most cases an addition of inoculants to molten cast iron is advisable and even necessary to produce good-quality castings. The mechanical properties and machinability of cast iron with nodular graphite greatly depend on the formation of graphite and the matrix microstructure and both are significantly influenced by the inoculation treatment. The mechanism of inoculation, the influence of the inoculation method and the amount of added inoculants are presented. Keywords: ductile iron, inoculation, microstructure, graphite, metallic matrix V ve~ini primerov je dodatek modifikatorjev staljenemu livnemu`elezu priporo~ljiv in celo potreben za izdelavo dobrih ulitkov. Mehanske lastnosti in obdelovalnost litega`eleza z nodularnim grafitom so mo~no odvisne od oblike grafita in od mikrostrukture osnove, na oboje pa mo~no vpliva obdelava z modifikatorji. Predstavljen je mehanizem modifikacije, vpliv metode modifikacije in vpliv koli~ine dodanega modifikatorja.
Austenitic stainless steel is mostly used at high temperatures. It is known that during heating of the austenitic stainless steel with increasing temperature and time of annealing a microstructure is changed i.e. there is the precipitation of carbides followed by precipitation of secondary phases as a sigma phase. The presence of the delta ferrite in austenitic stainless steel enhances the formation of the sigma phase. This study represents the influence of delta ferrite on the sigma phase formation and the effect of the sigma phase on general corrosion. Corrosion tests were conducted in the corrosion cell according to Standard ASTM G5, on instrument potentiostat/galvanostat, Princeton Applied Research, model 263A-2, with the software PowerCORR® (Standard, ASTM G5-94). Examinations were carried out in 1% HCl and 10% FeCl3 solutions. The Tafel extrapolation method was used for the investigation of general corrosion. The results of corrosion testing indicated that the intensity of the general corrosion increases with the
increase of the delta ferrite and sigma phase contents.
Sulphur in steel is an undesirable element because it lowers all technological and uses values of steel
products. During the steelmaking process, the desulphurization process depends on the thermodynamic
conditions, the used desulphurizes, and the stability of the formed sulphides. The desulphurization
technology in the production of low-carbon steel in a protective atmosphere, with the addition of
synthetic slag and strong desulphurizing agents with additional argon blowing, is presented in this paper.
The reduction of sulphur content achieved in the induction furnace is an important contribution to the
technology of the production of low-carbon steels.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.