Effect of temperature and time conditions of melting on the improvement in steel quality

Investigated are the standard quality factors of high-alloy steels and high alloys of various structural classes (Kh15N60, Kh12N1, Kh12, Kh20N80 and others) melted on a commercial scale in 5-10 t arc furnaces with 300-400 deg C superheating over the liquidus temperature and with reduced (by 30-80 deg C) casting temperature, hold times of the melt being carefully regulated. The experimental metal had a number of advantages in comparison with the metal of conventional technology. It differs in reduced shrinkage, increased mechanical properties (by 10-20%) and improved ductility in forging and rolling. Decrease in rejection on the intermediate stages provided the increase in metal yield by 5-6%. The improvement obtained in quality is explained by the effect of superheating on the structure and properties of the metallic melt before crystallization