Bottom-blown basic oxygen steel mfr. - oxygen followed by argon or nitrogen to reduce hydrogen content

摘要

This process is for mfg. steel with a pre-determined low H2 content in a bottom-blown basic oxygen converter by (a) blowing O2 surrounded by a protective hydrocarbon gas through one or more jets below the surface of the melt to lower the carbon content; (b) then blowing a hydrogen-free gas through the jets so the final H2 content Hf (ppm) is where H1 is the initial H2 content; V = vol. of the hydrogen free gas (s.c.f.); W = bath wt. (lbs); and K1 is the ratio of the mol. wt. of H2 x 106 to the product from 1 mole. gas under standard calibration conditions. The final steel pref. contains more than 0.1% C and one pref. method is to blow Ar through the melt for 2 secs. to 3 mins. to reduce the hydrogen, oxygen and nitrogen contents of the steel; other pref. methods are claimed. Mfr. of steel with low hydrogen content and/or low O2 and/or low N2, esp. carbon steel.