600 microns thin-specification 250 MPa high-phosphorus IF steel stable rolling method

Abstract

The invention relates to a 600 microns thin-specification 250 MPa high-phosphorus IF steel stable rolling method, and belongs to the technical field of thin-specification high-strength deep-pinching steel production processes. According to the technical scheme, firstly, the steel-making finally comprises the following chemical components of, in percentage by mass, 0.020%-0.04% of C, 0.30%-0.50% ofSi, 0.60%-0.80% of Mn, less that or equal to 0.012% of S, 0.08%-0.09% of P, 0.002%-0.01% of Ti, 0.04%-0.05% of Nb, 0.0005%-0.001% of B,and the balance Fe; secondly, the hot rolling heating temperature is 1200 +/- 20 DEG C, and the final rolling temperature is 870 +/- 20 DEG C, the reeling temperature is 700 +/- 20 DEG C; finally, the acid continuous rolling reduction rate is 76%-77%. The method has the beneficial effects that a certain amount of boron is added in the smelting process, the hot rolling process and the acid continuous rolling process are optimized, and the stable production of 600 microns thin-specification 250 MPa high-phosphorus IF steel is realized.

Description

technical field [0001] The invention relates to a stable rolling method for 250MPa high-phosphorus IF steel with a thickness of 600 μm and belongs to the technical field of production technology of thin-gauge high-strength deep-drawing steel in the metallurgical industry. Background technique [0002] With the continuous improvement of automobile lightweight, cost reduction and safety requirements, the proportion of thin-gauge high-strength deep-drawing steel used in automobile structural steel is increasing year by year. Phosphorus-containing high-strength IF steel can maintain excellent deep drawability and obtain high strength only through the intergranular strengthening effect of P. It has been widely used in automotive structural parts, especially phosphorus-containing IF steel with a strength of 250MPa and below. [0003] In the metallurgical industry, phosphorus in IF steel is easy to segregate at the grain boundary, causing cold-working brittle cracking to occur freq...

AI Technical Summary

Problems solved by technology

Unstable temperature control in hot rolling of high-phosphorus IF steel causes segregation of P elements and excessive reduction rate of recompression, resulting in brittle fracture of stacked steel due to fluctuations in plate shape and rolling force during hot rolling and acid rolling; hot rolling stock preparation 2.7mm and above rolling 600μm cold plate, high rolling force due to high reduction rate in the acid rolling process of strip steel, high tension deviation fluctuation, reduced rolling stability, and increased probability of strip strip deviation

[0005] Second, the shape and thickness fluctuations of the steel strip head and tail directly affect the welding quality, and the rolling force is unstable after entering the rolling mill, resulting in broken strips; the cutting blades of the disc shears have been used for a long time, and the cutting blades are aging and worn. The problem directly causes the quality of edge trimming to drop and leads to broken belt

[0006] Third, the pickling speed, acid concentration and acid temperature directly affect the pickling quality of its strip steel, thereby affecting the stability of its subsequent rolling, and the thickness of parking spots caused by too slow rolling speed and over pickling It often

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