METHOD FOR FREELY ROLLING SHAPES WITH FLANGE

摘要

PURPOSE:To prevent occurrence of web necking at the time of executing the large web expansion by oblique roll system in an intermediate rolling stage and to obtain products with a good distribution of web thickness even when web expansion is not executed. CONSTITUTION:At the time of executing rolling for expanding web height by arranging a pair of right and left oblique rolls in the insides of flanges of a material to be rolled between the intermediate rolling stage and finish rolling stage of shapes, recessed parts with a prescribed cross-sectional area that is determined from the target amount of expansion and web thickness of product are respectively provided on the peripheral surfaces in both right and left end parts of upper and lower horizontal rolls 2H of at least one or more universal mills RU in the intermediate rolling stage and excess metals 18 are formed in both end parts of web of a rolled stock. In a rolling stage in which a steel material which is screwed down with the upper and lower horizontal rolls 2H is not filled into the recessed parts, the degree of repletion of steel material into the recessed parts of the upper and lower horizontal rolls 2H is controlled by changing the ratio of flange draft and web draft or using it jointly with the movement of vertical rolls 2V to the inlet side or the outlet side of rolling and utilizing the adjusting action of metal flow from the flange to the web.