Double-stand rolling method for rolling super-thick steel plate by giving consideration to both plate shape and flaw detection performance

Abstract

The invention discloses a double-stand rolling method for rolling a super-thick steel plate by giving consideration to both plate shape and flaw detection performance, and belongs to the technical field of rolling of medium-thick plates. Through reasonably selecting billet type, a roughing mill adopts a mode of direct longitudinal rolling, instead of rolling through broadening, meanwhile, the thickness of steel plates at a controlled temperature is added 15-20mm based on that of a target thickness, so as to ensure that the overall rolling reduction at rough rolling phase reaches maximum, crystal grains in core part of the steel plates are fully refined to improve organizational performance of the core part; the overall rolling reduction at a finishing mill is 15-20mm, which is completed through three to five passes of rolling, the rolling reduction at the last pass is approximately 2-5mm, little rolling reduction functions to flatten the shape of the steel plates, thereby guaranteeing the shape of the steel plates.

Description

technical field [0001] The invention belongs to the technical field of medium and heavy plate rolling, and in particular provides a double-stand rolling method for extra-thick steel plates (steel plates above 140mm) that takes into account both the shape and flaw detection performance, and can simultaneously ensure the shape of extra-thick steel plates. and performance rolling methods. Background technique [0002] The experience of producing steel plates with guaranteed flaw detection performance at home and abroad generally requires that the compression ratio from billet to finished steel plate meet the condition of ≥3. At present, the thickest continuous casting slab that can be produced in China is 400mm, and the compression ratio of 400mm steel slab rolled to 150mm steel plate is only 2.7. Therefore, the technical difficulties in the development of extra-thick plate are mainly due to the small compression ratio, flaw detection performance and thickness direction perform...

AI Technical Summary

Problems solved by technology

At present, the thickest continuous casting slab that can be produced in China is 400mm, and the compression ratio of 400mm steel slab rolled to 150mm steel plate is only 2.7. Therefore, the technical difficulties in the development of extra-thick plate are mainly due to the small compression ratio, flaw detection performance and thickness direction performance of the finished steel plate Uniformity is difficult to guarantee

At the same time, extra-thick specification steel plates are prone to shape defects such as head and tail drifting during the rolling process, and the shape problems are extremely difficult to remedy through thermal straightening, so the output shape of the rolling mill must be strictly controlled

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