Control method of eliminating yield point elongation at front part and rear part of weld joint of cold-rolled strip steel

Abstract

The invention relates to a control method of eliminating yield point elongation at the front part and the rear part of a weld joint of cold-rolled strip steel and belongs to the technical field of cold-rolled strip steel production control. According to the technical scheme, the control method comprises the following steps: when the strip steel is continuously produced, an operator determines the minimum scrap cutting knife number at a strip tail and the minimum scrap cutting knife number at a strip head according to the following formula in light of speed of the weld joint passing through a temper mill, and then the operator sets the minimum scrap cutting knife number at the strip tail and the minimum scrap cutting knife number at the strip head at an outlet for roll dividing: Y1 is greater than or equal to ROUNDUP{(0.58595+0.01384*X) / 0.45, 0}; Y2 is greater than or equal to ROUNDUP{(5.48925-0.04198*X+0.000346*X<2>) / 0.45, 0}, wherein Y1 is the minimum scrap cutting knife number at the strip tail, Y2 is the minimum scrap cutting knife number at the strip head and X is the speed of the weld joint passing through the temper mill, the unit of the speed is m / min; 0.45 is the length of scrap cut at the outlet every time and the unit is m. The control method provided by the invention has the beneficial effects that the control method is simple; the operator sets the speed of the weld joint passing through the temper mill according to rhythm of production and sets the corresponding minimum scrap cutting knife numbers at the front part and the rear part of the weld joint at the outlet, so that objection about quality caused by defects of fish scales as the head and tail are not thoroughly cut off is reduced while the product quality is guaranteed, and meanwhile, the production efficiency is increased.

Description

technical field [0001] The invention relates to a control method for eliminating the front and rear yield platforms of cold-rolled strip steel welds, and belongs to the technical field of cold-rolled strip steel production control. Background technique [0002] With the continuous development of the automobile industry, the market demand for cold-rolled automotive steel is increasing year by year. Cold-rolled low-carbon steel, high-strength low-alloy steel, phosphorus-containing high-strength steel and other steel types are widely used in automotive stamping parts. Forming use. Cold-rolled low-carbon steel, high-strength low-alloy steel, phosphorus-containing high-strength steel and other steels have their own characteristics. After recrystallization annealing after cold rolling, the steel is very soft and has obvious yield near the yield limit during tensile deformation. Platform phenomenon, which is related to the pinning dislocation of interstitial solid solution atoms i...

AI Technical Summary

Problems solved by technology

During cold rolling production, in order to maintain continuous production, the tail of each coil will be welded to the head of the next coil. The quality of the weld is relatively poor. If the weld does not reduce the rolling force and reduce the leveling amount when passing through the tempering machine It is very easy to break the belt at the weld seam, which seriously affects the production efficiency. At the same time, it will scratch the work roll surface of the temper machine, and then scratch the surface of the steel plate. Therefore, when the weld seam passes through the temper machine, the rolling force will gradually drop to the equipment After the minimum value of , it will gradually increase, and the leveling amount will gradually decrease to 0 and then gradually increase to the process requirement value. Therefore, there must be a section of strips with slowly decreasing and rising flatness before and after the weld that cannot meet the process requirements. This part of the product will be issued to When the customer stamps and uses the surface of the steel plate, there will be defects similar to fish scales, and the car factory cannot use it. For this reason, quality complaints have been made many times, which seriously affects the market promotion.

The measures adopted in the prior art are as follows: one is to increase the strip before and after the cut weld at the outlet, on the one hand it cannot guarantee whether the cut is clean, and on the other hand the waste of cutting is large; The braking force and leveling amount do not change, and the normal rolling is leveled. Due to the relatively fast leveling speed, it is very easy to have a broken belt accident at the weld, which seriously affects the production efficiency.

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