GB699209A - A method for producing structural steel of high yield strength - Google Patents

Abstract

Highly dispersed oxidic inclusions are produced in unalloyed steel (i.e. those containing less than 0.5 per cent Si, less than 0.8 per cent Mn, less than 0.1 per cent Al or Ti, less than 0.25 per cent Cu with other impurities less than 0.1 per cent) and low alloy steels (i.e. containing up to 0.25 per cent C and up to 1.75 per cent Mn and/or 0.8 per cent Si and/or 0.3 per cent Mo and/or 0.5 per cent Cu and/or 0.1 per cent Al and/or 0.1 per cent Ti and/or 0.05 per cent Mg) to increase the yield strength by melting the steel in a basic open-hearth furnace in the ordinary manner or in a basic open-hearth furnace or basic converter with high oxygen blast, the final slag having a ferrous oxide content exceeding 20 per cent, and adding more than 0.5 kg/ton Al or more than 0.2 kg/ton Ti and/or Mg. Preferably the steel is melted and poured into a ladle in contact with a slag having more than 20 per cent ferrous oxide, when the additions are made. The additions may be made in the form of ferro-alloys.