Technology for eliminating withdrawing and straightening lines on surface of galvanized door plate steel

Abstract

The invention discloses a technology for eliminating withdrawing and straightening lines on the surface of galvanized door plate steel. The technology comprises the steps of pickling, rolling, cover type annealing, flattening and galvanizing. The selected galvanized door plate steel comprises 0.01 wt% or less of C, 0.04 wt% or less of Si, 0.15-0.25 wt% of Mn, 0.02 wt% or less of P, 0.015 wt% or less of S, 0.015-0.055 wt% of Al, 0.004 wt% or less of N, and 0.001-0.002 wt% of B. The galvanizing is carried out after the rolling in a general technology for the galvanized door plate steel, the route of technology in the invention is afresh designed and is characterized in that trip steel does not enter the galvanizing line, enters a cover type annealing furnace and is completely annealed, so the defect of incomplete annealing of the strip steel in a galvanizing and continuous annealing furnace is avoided, and complete annealing realizes the elimination of the residual stress in the strip steel and thorough removal of the yield point elongation from the strip steel, thereby withdrawing and straightening line defects on the surface of the strip steel are improved and removed after the galvanizing.

Description

technical field [0001] The invention relates to a process for eliminating tensile strain on the surface of galvanized door plate steel. Background technique [0002] Develop cold-rolled galvanized door panel steel products. After the products are produced, they are transported to the customer site for new product trials. During the product trial process, the customer feedback that the surface of the galvanized door panel steel is more serious. Due to the quality defect of surface tension correction, it has not been recognized by customers. [0003] Tensile straightening defects refer to the transverse lines that occur on the upper and lower surfaces of the strip steel after tension leveling, with small intervals (<2mm) and small widths (<0.5mm), and are randomly distributed on the entire strip surface. Corrosion of the coating on the stretched part will reveal the same texture on the strip steel substrate. Defects of tensile strain not only affect the appearance of t...

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Problems solved by technology

In all the retrieved documents, some of the article descriptions on the tensile-straightening defects on the surface of galvanized door panel steel are adjusted by adjusting the temperature system of the continuous annealing furnace, and some are adjusted by the elongation of the tension-leveler or the quality of the roll surface, but The treatment and control of this kind of defect have not fully achieved the effect, and the defect of surface tension correction is still relatively serious. In the production of galvanized door panel steel, which has relatively high quality requirements, it is impossible to have such serious defects on the surface. Allowed

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