Hot-rolling technology method for improving surface quality of car outer plate

Abstract

The invention provides a hot-rolling technology method for improving the surface quality of a car outer plate. The method comprises the steps that firstly, a supplied material enters a plate blank heating furnace to be heated to 1200 DEG C-1240 DEG C; secondly, weak oxidizing atmosphere is adopted in the heating furnace, and time for the plate blank in the furnace is smaller than or equal to 220 min; thirdly, after the plate blank is discharged from the furnace, oxidized scale generated in the furnace is removed; fourthly, the plate blank is roughly rolled through two rough rolling machines for 6 or 8 passes to be manufactured into a middle blank with the thickness within the range from 30 mm to 50 mm; fifthly, the head of the middle blank is shorn in a flying manner at an inlet of a finishing mill, and the oxidized scale is removed; sixthly, a finishing mill set completes a final product, and the target final rolling temperature range is between 910 DEG C and 950 DEG C; seventhly, thefinished product strip steel is cooled to 710 DEG C-750 DEG C; and eighthly, after rolling and cooling are finished, the finished product strip steel is rolled into a steel roll to be transported toa roll warehouse and stored. According to the hot-rolled strip steel prepared through the method, when the finished product strip steel obtained after cold rolling is completed is punched and polished, longitudinal stripe defects on the surface are avoided, and during metallographic inspection over the cross section of the strip steel, non-recrystallization layers are not found.

Description

technical field [0001] The invention belongs to the technical field of hot rolling, and relates to a hot rolling process method for improving the surface quality of an automobile outer plate. Background technique [0002] In the existing IF steel rolling process, due to the temperature difference between the head and the tail and the temperature drop at the edge, the phenomenon of 880-890 ° C in the strip will appear locally, which will lead to mixed crystals in some areas and cause edge defects. In the process of providing the outer panel of the automobile, the defect of stamping stripes appeared, and the metallographic examination of the strip steel section found an unrecrystallized layer, which affected the performance of the finished product. Contents of the invention [0003] In order to solve the above-mentioned technical problems, the object of the present invention is to provide a hot rolling process method for improving the surface quality of the outer panel of th...

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Problems solved by technology

[0002] In the existing IF steel rolling process, due to the temperature difference between the head and the tail, the temperature drop at the edge, etc., there will be a phenomenon of 880-890°C in the strip steel, which will lead to mixed crystals in some areas, resulting in edge defects

In the process of supplying the outer panel of the automobile, the defects of stamping stripes appeared, and the metallographic examination of the steel strip section found an unrecrystallized layer, which affected the performance of the finished product

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