In the actual production, the reasons affecting the buckle of rolled pieces are complicated, and the interaction between many factors makes it difficult to restrain the buckle of a single factor. In view of this situation, it is necessary to comprehensively consider the process, equipment, electricity, model and other aspects to solve. In the actual production process, our factory mainly adopts the following methods to control the phenomenon of rolled buckle head.
1) Improve the uniformity of rolling temperature. First of all, the heating furnace adopts the two-stage mode to burn steel, which ensures the uniformity of the temperature of the rolled parts. Secondly, in the rolling process, the leakage of the cooling water of the upper work roll is reduced, especially for the control rolled steel plate, and the number of descaling passes is reduced as much as possible during the finishing rolling. In addition, as permitted by the equipment, the use ratio of the upper and lower roll cooling water is appropriately changed.
2) Reasonable development of rolling process regulations, optimization of rolling model, to ensure the flatness of the steel plate. In actual production, according to the existing rolling technology, summarize the shortcomings, constantly optimize the rolling model, make different rolling technology according to different steel grades, rationally distribute the rolling force and the reduction amount of each pass. Through discussions with Siemens technicians and automation personnel, control functions such as "minimum number of finishing passes", "maximum rolling force at last pass" and "maximum reduction amount of smoothing pass" have been added to the rolling model. The "minimum number of finishing passes" is mainly used to control the crown of the finished steel plate, the finishing rolling temperature and the wave shape of the steel plate. The "maximum rolling force of last pass" mainly controls the rolling force of finishing pass, controls the deformation zone of head and tail is too large, and ensures the flatness of the steel plate; "Last pass reduction amount" is to control the leveling pass value in 0~ 8mm, which plays a leveling role. At present, this procedure is mainly for steel plates with the target thickness of 30 mm and above. By optimizing the rolling model, the buckle head of rolled parts has been reduced to a great extent.
3) At the instant stage of biting, the buckle head is controlled by optimizing the SKI function. SKI is also known as sleigh rolling, that is, adjusting the speed difference of the upper and lower work rollers to control the buckle and tip of the steel plate. The main motor of the upper and lower work rollers in our factory adopts a separate drive. According to the rolling principle, allospeed rolling can effectively improve the shape of the head. If SKI is positive, increase the tilt of rolled parts or reduce the degree of buttoning. (V is the speed of the upper work roll in finishing rolling; Under V is the speed of the lower work roll); We optimize the SKI adjustable length, that is, the adjustable length can be selected for each roll pass. The SKI value is adjusted according to the actual shape of the steel plate on site, which greatly reduces the appearance of the buckle of the rolled piece.
4) Our factory's AGC hydraulic cylinder in the lower part of the rolling mill, can properly adjust the height of the rolling line to inhibit the phenomenon of buckling head in the rolling process.
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