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¡¡¡¡The hot rolled strip is cooled by laminar flow to room temperature, and the temperature difference between the edge and the middle part may cause bilateral waves and affect the shape of the strip. One solution is: using micro wave rolling mill, namely at the exit of the finishing mill, the shape adjustment effect of control mechanism, to a certain extent in the micro strip wave to offset the difference caused by bilateral wave. Another method is: using the edge temperature control technology on the strip, such as edge heating technology and side cooling water shield, ensure the edge and middle part temperature, can improve the shape quality of strip, ensure the uniformity and performance of horizontal organization.
¡¡¡¡The ultra fast cooling technology is an important measure to ensure the strip material uniformity, using continuous cooling water, clouds, with certain pressure, spray to the surface of the steel plate, steel plate surface may exclude film boiling and transition boiling, the implementation of ultra fast and uniform cooling of steel plate overall. This keeps the flatness of the steel plate and improves the performance of the material. Roller type direct quenching technology using high pressure jet cooling water to the steel surface at a certain angle, remove the gas film between the steel plate and the cooling water, can get good plate straightness, and can improve the hardenability and uniformity. A "Super-OLAC" technology, that is, "suction type cooling with a high density catheter", has been applied to control cooling of a new generation of medium plate in recent years, and the surface temperature of the cooled steel plate has been uniformly distributed.
¡¡¡¡In order to solve the rolling load to roll deflection resulting in steel plate wave shape and the width direction of the side convex problems, MITSUBISHI heavy industries and Nippon Steel joint development of HC (highcrowncontrol) PC (paircross) and rolling mill for plate shape control. The so-called HC mill, between the support roller and the work roll is equipped with an intermediate roller that can move in the axial direction, because the roll lateral rigidity increases, the rolled steel plate has good flatness. Although the work roll diameter is small, but can ensure lateral rigidity, meet the control requirements of plate shape and plate crown. The small diameter of the work roll can reduce the rolling load so as to achieve the effect of energy saving. The so-called PC mill is to keep the working roll shaft and the support roller balanced, so that the upper and lower roller groups cross rolling. PC mill and the ability to control the plate shape and convex is stronger than that of HC mill. PC mill is mainly used in tandem rolling mill, while HC mill is used as shape control of cold rolling mill.
¡¡¡¡Steel mill in AISC 2150 hot rolling high strength pipeline steel, LVC work roll upstream stand using a self-developed and roll shifting and bending the downstream stands by routine work roll, support roll with varying contact rolling technology, the shape control level of rolling high strength pipeline steel has been greatly increase length of crown control qualified rate increased from 18.79% to 96.27%.
¡¡¡¡In order to control the flatness of strip plate better, the powerful bending roll technology, the roll shifting technique and the roll cross technology can be used to control the finishing mill. In modern cold rolling mill, four high mill, six high mill, cross rolling mill and four roller mill with rolling roll are usually used to obtain high quality and high dimensional precision products.