Method for improving ultra-fast cooling uniformity of medium and heavy plate after rolling

Abstract

The invention relates to a method for improving the ultra-fast cooling uniformity of a medium and heavy plate after rolling, the position of a jet flow header can be reasonably adjusted, and the method is characterized in that, 1) the position of an upper header is set as follows: an ultra-fast cooling upper header framework is adjusted up and down in the vertical direction, and the conditions ofthe formula: Hu*tg(theta)=Hd*tg(theta)+D are met; 2) the setting of a soft water seal of a washing water region on the upper surface of a steel plate meets the conditions of the formula: 1 / 2*the sum of flow rates of all forward headers in the region<water amount of the soft water seal<2*the sum of the flow rates of all the forward headers in the region; 3) the flow rate of a lower header is increased to compensate the heat exchange capacity of the lower surface, and the optimal ratio of water supply to water discharge is set to be between 1: 1.1 and 1: 2.5; 4) the measure of clearing residualcooling water on the upper surface is taken, side spraying devices are arranged on the two sides of an ultra-fast cooling roller table, a middle spraying device is arranged on the upper header framework and strong blowing devices are arranged at the two ends of the ultra-fast cooling device; and 5) the head and tail shading control of the speed of the roller table is performed as follows: an ultra-fast cooling control system is used for transformation control of the speed of the roller table of a steel plate head and a tail part low-temperature region according to a speed curve. By adopting the method, the cooling uniformity of a steel plate of the medium and heavy plate after rolling under ultra-fast cooling condition can be realized.

Description

technical field [0001] The invention relates to a cooling process for rolling steel, in particular to a method for improving the uniformity of ultra-fast cooling after medium-thick plate rolling. Background technique [0002] In recent years, more and more attention has been paid to the controlled cooling technology after plate rolling. At the same time, as the cooling temperature develops to the low temperature region, the cooling rate increases, and the residual stress and plate shape problems caused by uneven cooling are particularly prominent. It can be said that the plate shape control under the condition of high cooling rate has become a bottleneck problem in the development of high-strength steel using TMCP technology. If effective cooling uniformity improvement measures are not adopted, serious cooling non-uniformity and even serious plate shape problems will occur under the condition of ultra-rapid cooling after medium-thick plate rolling. The reason is that under...

AI Technical Summary

Problems solved by technology

For ultra-fast cooling systems, the water supply method usually uses pumps to directly supply water. If flow changes or header opening and closing are used, it will have a greater impact on the stability of the water system and affect the stability of the cooling system.

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