| 摘要 |
PURPOSE:To manufacture the title beam by subjecting a low carbon billet contg. specific small amounts of Cr and having low S content to hot finish rolling, working it into a wide flange beam and thereafter rolling down the internal and outer faces of the flange part by a roll. CONSTITUTION:A steel billet contg., by weight, 0.05 to 0.20% C, 0.01 to 0.10% Si, 0.20 to 1.50% Mn, 0.001 to 0.010% S, 0.005 to 0.080% Al and 0.05 to 1.00% Cr is heated to 1000 to 1300 deg.C and is subjected to hot rolling to work into a wide flange beam stock, which is thereafter subjected to finish rolling to manufacture a wide flange beam. The flange part of the flange beam 6 is rolled down from the internal and outer direction by vertical rolls 9a to 9d inside of the flange and the adhesion of scale inside of the flange is improved into tight scale, by which the wide flange beam having excellent peeling resistance of scale and having no generation of red rust can be manufactured. |
