Method for rolling 40-100 mm medium-thickness plate with corner cracks of continuous casting billet without cleaning and with low edge cutting amount

Abstract

The invention discloses a method for rolling 40-100 mm medium-thickness plate with corner cracks of a continuous casting billet without cleaning and with the low edge cutting amount, and belongs to the technical field of steelmaking-steel rolling. The method for rolling the medium-thickness plate comprises the steps that molten iron smelting is conducted, the continuous casting billet is obtained through casting, quality inspection needs to be conducted on the casting billet before the casting billet is heated, the quality inspection content comprises the steps that the actual width B0 of the casting billet and the crack widths B1 and B2 of the corners of the two sides of the casting billet are measured, and whether the casting billet needs to be cleaned or not is determined according to the crack strip width of the casting billet and the rolling broadsiding ratio. By controlling the heating and rolling process, the flattening width is controlled within the design range, when the total edge cutting amount of the two edges of the rolled steel plate is 70-100 mm, cleaning-free rolling of the crack within 25 mm of the edge portion of the single edge of the continuous casting billet can be achieved, the flattening width of the single edge of the steel plate obtained after rolling is controlled within 15 mm, and a corner crack strip is controlled within the edge cutting amount range; and during finishing, cutting off can be achieved, therefore, the corner cleaning cost of the casting billet with the corner cracks is reduced, the yield is greatly improved, and the method has remarkable economic benefits.

Description

technical field [0001] The invention relates to the technical field of steelmaking-steel rolling, in particular to a method for rolling 40-100mm medium-thick plates without cleaning the cracks at the corners of continuous casting slabs and with low trimming. Background technique [0002] The problem of transverse cracks at the corners of continuous casting slabs is a key quality problem that plagues continuous casting production, and it is also a problem that is difficult to completely solve in various steel mills. It not only restricts the application of hot charging and hot delivery, but also seriously hinders contract performance and increases production costs. [0003] Especially for continuous casting slabs with a large cross-section of 300mm and above, the problem of transverse cracks at the corners is particularly common. The proportion of transverse cracks at the corners of continuous casting slabs in an enterprise reached about 90%, and the cleaning pressure task w...

AI Technical Summary

Problems solved by technology

[0006] The method described in this patent requires a compression ratio greater than 5-25, and is mainly suitable for rolling thin plates with a thickness of 10-40mm. For rolling steel plates with a thickness of 40mm or more, rolling The production of thick plates with a compression ratio of only 3-8 does not provide a clear control method for edge cracking; at the same time, the patent rolls a bilateral trimming amount of 76-126mm, and the range of trimming amount is relatively large, and no clear setting is given The calculation formula of trimming amount is not convenient for actual operation and control

At the same time, the corner cracks of carbon-containing Nb steel in this patent are less than 15mm, and the corner cracks of ordinary carbon and low alloy steels are less than 20mm to realize free-cleaning rolling. Corner cracks above 20mm must be cleaned and corner-cut