| 摘要 |
PURPOSE:To obtain the wide flange shape by means of hot rolling by combining rapid cooling for a fillet part with flange spacing reduction rolling under specific conditions. CONSTITUTION:In the course of rolling for a wide flange shape by means of hot universal mill rolling, local cooling is applied at >=5 deg.C/s cooling rate to a fellet part corresponding to the internal angle between the flange and web of the wide flange shape, on the inlet side of the final pass or the pass just before the final pass. This cooling is performed by applying water cooling to the external surface of the flange at the center of flange width, by which crystalline grains can be refined. Then, the fillet part is subjected to heat balance (balance between heat radiation from the steel surface and internal thermal diffusion) at a temp. between the Ar1 point and 630 deg.C, and web-height-direction squeeze rolling where flange spacing is reduced by the length >=10mm and <=4 times the thickness of the web is exerted. By this method, the amount of working strain applied to the fillet part can be increased and crystalline grain refining can be accelerated to a greater extent, and further, superior strength and toughness can be obtained. |
