Method for preparing hot rolling strip steel capable of preventing edge crack of extremely thin rolled strip steel

Abstract

The invention relates to a method for preparing hot rolling strip steel capable of preventing edge crack of extremely thin rolled strip steel. The method comprises the following steps of: (1) smelting, namely desulfurizing molten iron, smelting by using a converter, blowing argon at an argon station, and performing continuous casting to form slabs; (2) performing hot rolling, namely heating the slabs to 1,210 to 1260 DEG C, wherein the temperature difference of the same slab is less than or equal to 30 DEG C; performing rough rolling, and finish rolling, wherein the side pressure delta B when the slab with the width B is subjected to rough rolling is controlled according to the following formula: delta B ranges from 35*B/1,250*(B-1,050)/(1,250-1,050)+35*B/1,050*(1,250-B)/(1,250-1,050) to 50; and finally reeling to obtain the hot rolling strip steel. The method is simple and practical, is stable in use and high in uniformity, reduces the alloy cost and shortens the production cycle; and the steel plate heat commercial (SPHC) hot rolling strip steel prepared by the method has the obvious effect of preventing the edge crack of extremely thin cold-rolled sheet.

Description

technical field [0001] The invention belongs to the field of steel strip preparation, in particular to a method for preparing hot-rolled steel strips capable of avoiding edge cracks in rolling extremely thin steel strips. Background technique [0002] In the Yangtze River Delta region of my country, the construction industries such as home appliances and color plates are very developed, and most of them use low-carbon steel materials, ultra-thin cold-rolled sheets, galvanized sheets, and color-coated sheets with a thickness of less than 0.5mm. Most of the domestic cold rolling mills producing this kind of products are medium-sized private enterprises, generally adopt single-stand or double-stand reversible cold rolling units, and use low-carbon hot-rolled strip steel to manufacture ultra-thin strips with a thickness of 0.15-0.39mm. Cold-rolled steel strip, due to its high cold-rolling tension, fast rolling speed and high total reduction rate, is prone to defects such as narr...

AI Technical Summary

Problems solved by technology

The disadvantages are: ① increase production equipment; ② use hot rolling oil, increase production costs, pollute the environment of the production site, and increase equipment maintenance costs; Edge Cracking of Thin Strip Steel

[0006] In May 2005, Hu Hongxu of Anshan Iron and Steel New Rolling Co., Ltd. applied for an invention patent "Control method for pickling and trimming of ultra-low carbon mild steel" (patent publication number CN 1858666A, publication date November 8, 2006), which is characterized by The trimming parameters of the horizontal and vertical gaps of the disc shears are calculated by a mathematical model that is linearly related to the thickness of the raw material through the process computer. After the actual test and application on site, the finished cold-rolled strip steel sawtooth The amount of defects such as edge and edge cracks has decreased by about 55% compared with before; however, the problem of edge cracks in finished cold-rolled strips has not been completely solved

[0007] Although most domestic iron and steel enterprises are required to control the Mn / S value in the steel above 20 (or even 30) in order to suppress the transverse micro-cracks at the edge of the steel plate when producing hot-rolled coils for ultra-thin cold-rolled strip steel, but in In steel plants such as Ningbo Iron and Steel Company, in order to reduce production costs, the S content of steel scrap auxiliary materials and molten iron used for smelting remains high. To increase the Mn / S value, the Mn content has to be increased, so that the smelting cost of the product will rise to a certain extent

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