Prevention of cracking of continuously cast steel slabs containing boron
AssigneeNippon Steel Corporation
InventorsHiroo Suzuki, Koichi Yamamoto, Yasuhide Ohno, Kou Miyamura
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Abstract
Production of boron-containing steel slabs free from surface defects by continuous casting, particularly prevention of the slab surface crackings by cooling the slab with a specific cooling rate through the temperature range from the melting point to 900.degree. C. so as to prevent boron-containing compounds such as BN from precipitating along the austenite grain boundary. Great advantage over the conventional art is that boron-containing molten steels which could not be continuously cast can be successfully continuously cast into slabs free from surface defects.
Claims5
A method for preventing crackings of boron-containing steel slabs in continuous casting of molten steels containing nitrogen and boron in amounts falling within Zone II defined in FIG. 2, which comprises cooling the steels through a range of from the melting point to 900.degree. C. with an average cooling rate ranging from 0.01.degree. to 1.degree. C./sec. to prevent precipitation of boron-containing compounds along austenite grain boundaries thereby promoting precipitation of the boron-containing compounds in the austenite grains.
Dependencies are inferred from the claim text.