A production method of cold-rolled continuous annealing wide-width plate that improves short-line rubbing and scratching defects

Abstract

The invention relates to the technical field of rolling, in particular to a production method of cold-rolled continuous-annealing wide-width plate for improving short-line scratch defects. The production method of the cold-rolled continuous annealing wide-width plate designed by the present invention to improve short-line scratch defects includes ironmaking, steelmaking, continuous casting, hot-rolling and acid rolling, cold-rolling and acid-rolling, and continuous annealing processes; In the hot rolling process, the thickness of the hot-rolled incoming material needs to satisfy the relational formula: H=‑0.5h 2 +2.5h+3, wherein H is the thickness of the hot-rolled incoming material, h is the thickness of the cold-rolled finished product, and the convexity is controlled at 50±20 μm; in the hot-rolled and acid-rolled process, the total reduction rate is controlled to be 50-80%, The unevenness is controlled at ≤10I; in the continuous annealing process, the tension difference between the driving side and the operating side in the furnace is controlled to be ≤10%, the content of the hydrogen atmosphere in the furnace is 5-10%, and the dew point of the first heating zone is controlled to be ≤-30°C . The invention can effectively reduce the longitudinal and transverse short-line rubbing and scratching defects of the wide-width board.

Description

technical field [0001] The invention relates to the technical field of rolling, in particular to a production method of cold-rolled continuous-annealing wide-width plate for improving short-line scratch defects. Background technique [0002] Since the width of the wide-width slab is ≥1800mm, in the cold rolling process, due to reaching the limit of the equipment, it is more difficult to control the width of the small-width slab, and surface defects are more likely to occur. The surface defects of the wide-width slab are mainly reflected in the running direction. Horizontal and vertical short-line defects generally appear in clusters, and such defects will seriously affect the surface quality of wide-width plates. [0003] For example, the Chinese invention patent with the application number 200910011959.4 proposes a method for reducing fold defects of cold-rolled steel coils. After cold-rolling, the steel coils enter the continuous annealing furnace for recrystallization ann...

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Problems solved by technology

However, none of the above documents involves the control method of longitudinal and transverse short-line defects of wide-width plates.

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