GB1267942A - Continuous steel casting method - Google Patents

Abstract

1,267,942. Continuous casting. ROBLIN INDUSTRIES Inc. 25 March, 1969 [18 July, 1968], No. 15520/69. Heading B3F. [Also in Divisions C7 and F4] To reduce the amount of oxide inclusions greater than 20 microns in size in a continuously cast strand, the steel to be cast is teemed from a ladle 10 to maintain, possibly by automatic control, a constant head in a tundish 16 and the melt passing from there to at least one reciprocated mould 22 or 24 is protected in an atmosphere of argon which is continuously changed to deoxidize the stream. O 2 in solution in the steel is said to be removed, oxides reduced and CO formed and removed. The argon is fed from holes 72, Fig. 2, in a cross-piece 66 at the end of a tube 62, into a space 74 enclosed by a porous woven sleeve 45 of asbestos surrounding each melt stream 76. It bleeds out of the space at 23 c.ft.(min., when casting two 4-inch square billets, to give a rate of about 48 c.ft./ton of steel. The sleeve 45 is clipped to flanged end collars 36, 38 which are pressed apart by a spring 42 to seal against a mould top and a slide valve assembly 32 on the tundish. 16. A graphite insert 60 prevents welding of the slide-plate 54. Two baffles 80, 82 across the tundish facilitate separation of inclusions to form slag at the surface of the melt in the tundish. Ca and/or Si are used as deoxidants in the ladle to obtain an oxygen content in the solidifying steel of 40-90 parts per million.