A process for eliminating stretch marks on the surface of galvanized door panel steel

Abstract

The invention discloses a process for eliminating stretch marks on the surface of galvanized door panel steel. The selected process route is: pickling-rolling mill-bell annealing-leveling-galvanizing; the weight of each chemical component in the selected galvanized door panel steel Percentage % is C≤0.01, Si≤0.04, Mn 0.15‑0.25, P≤0.02, S≤0.015, Al 0.015‑0.055, N≤0.004, B 0.001‑0.002; usually the process of galvanized door panel steel is after it comes out of the rolling mill enter the galvanizing line for production, but in the method of the present invention, the process route has been redesigned. After the rolling mill is rolled out, it does not enter the galvanizing line, and the strip steel flow direction is first adjusted to enter the bell annealing furnace for complete annealing. The main purpose of the adjustment is to avoid the defect of incomplete annealing of the strip steel in the galvanizing continuous annealing furnace. Due to the complete annealing, the residual stress inside the strip steel is eliminated, and the yield platform of the strip steel is completely removed, so that it can be straightened after galvanizing. It will improve and remove the tensile strain defects on the surface of the strip.

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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