ROLLING FORCES IN THE PRODUCTION OF I BARS FROM CONTINUOUS-CAST BILLET ON A 450 MILL

摘要

All-Russian State Standard COST 26020 has been developed in order to improve the range of I bars and reduce the costs in manufacturing metal structures and mechanisms by the Ukrainian Scientific-Research Institute of Metals and the TsNIIPSK Institute. For the sake of standardization, the dimensions of I beams 10B1, 12B2, 14B2, 16B2, 18B2, and 20B1 with parallel crosspiece faces are adopted in accordance with the DIN 1025.5 and Euronorm 19-57 standards. Lighter types 12B1, 14B1, 16B1, and 18B1 have been introduced. Until 2001,1 beams were rolled on a 450 mill in accordance with All-Union State Standard COST 8239, for beams where the internal crosspiece faces are inclined (Fig. la) and with COST 26020 for I beams of type B2 (Fig. lb,c). The energy, temperature, and speed parameters of rolling permit the manufacture of such profiles. The dimensions of the final profile are within the relevant tolerances. However, the existing system does not permit the rolling of I beams of type Bl with reduced thickness of the neck and flanges in the roughing group, as confirmed by the experimental rolling of a 16B1 I beam. After cell 9, the billet has been rolled with increase in the reduction over the profile elements in universal cells. Altogether, 3000 tons are rolled, but the rolling rate is no more than 5 m/sec on account of the large load of the universal cells. In rolling, the flanges sometimes break away from the I-beam wall at the front end of the piece and the profile obtained is within the zone of plus tolerances.