PURPOSE: To produce a thin-walled web and H-beam without waving of a web by forming the web of the H-beam subjected to finish rolling to a prescribed shape in the height direction so as to have a curved sectional shape and cooling the same then returning the web to a linear sectional shape at a specific draft and flattening and straightening the web.
CONSTITUTION: The thin walled web and H-beam 8 is subjected to finish rolling by a universal finishing mill to ≥2 ratio between the wall thickness of the flanges and the wall thickness of the web. The web of the H-beam 8 is then formed with the curved sectional shape deformed to the outside of the surface of a pair of rolls 21, 22 in the height direction thereof and is cooled. The web of the H beam 8 subjected to curving and forming is further rolled down at 0.2W10% by a cold rolling mill 5 to return the curved sectional shape to the initial sectional shape and thereafter the web is flattened and straightened by a roller straightener. The waving of the web is thereby obviated and the product having good quality is stably and efficiently obtd.
IIDA NAKAO
KUSABA YOSHIAKI
