Characteristics of main models of stainless steel cold rolling mill

author: glimpse technology

2022-11-10

Characteristics of main models of stainless steel cold rolling mill

Topic description: This paper summarizes the main cold rolling mill types and their characteristics used in domestic stainless steel cold rolling production. When selecting the type of stainless steel cold rolling mill, stainless steel cold rolling enterprises should integrate the main characteristics of the mill and the use of the products produced by the investor, so as to reasonably determine the type of machine, improve the cost performance ratio of equipment investment, ensure the proper selection of equipment, improve the output and quantity of production products, and achieve the best benefit of capital investment and equipment investment.
Keywords: four high mill, six high mill, partial eight high mill, twelve high mill, twenty high mill
Cold rolled stainless steel is becoming more and more important in the development of national economy and the daily life of the public because of its wide use. As it is a special steel, the product types and specifications are complex, and it can be divided into three series, namely, 200 series (chromium manganese series), 300 series (austenitic), and 400 series (ferritic) stainless steels. Each series has a variety of steel grades with different brands, which have different special uses, and there are also large differences in the industry and field of application. Therefore, the stainless steel production process is not only complex but also special, which is different from that of ordinary steel.
At present, private enterprises engaged in stainless steel cold rolling production in China fall into two categories:
A kind of enterprise that only produces 400 series stainless steel products. As 400 series stainless steel has the smallest pass rolling pressure, good ductility of the plate, and low requirements on the comprehensive rolling performance of the equipment, such stainless steel cold rolling enterprises select more or less four roll reversing cold rolling mills. A few enterprises adopt the selection concept of ordinary carbon steel enterprises, and some of the wide plate mills use six roll reversing mills.
Another kind of enterprises rolling more than 200, 300 and 400 series stainless steel products at the same time. There are many kinds of rolling mills selected by such enterprises, including four high reversing rolling mill, partial eight high reversing rolling mill, twelve high reversing rolling mill and twenty high reversing rolling mill.
In the cold rolling stainless steel enterprises, there are not only the above main models, but also a small number of 18 high four layer roll system and 18 high three layer roll system rolling mills. As the four layer roll system 18 high rolling mill is a simplified model of the 20 high rolling mill; The 18 high mill with three layer roll system belongs to the improved type of six high mill;
The characteristics of the main models are summarized as follows:
（1） Four high mill
The traditional four high rolling mill adopts a two-layer roll system, namely, two backup rolls and two work rolls. The work roll drive mode cannot adapt to the production of stainless steel 200 series and 300 series because the work roll drive is affected by the drive torque. Therefore, the four high rolling mill adapted to the production of stainless steel uses a small roll diameter work roll and a backup roll drive mode, but the roll system has no twitch function and does not have the means to adjust the edge wave of the plate.
（2） Six high mill
The traditional six high mill is a three layer roll system, namely, two backup rolls, two intermediate rolls, and two layer work rolls. The work roll drive mode is used for the production of 200 series and 300 series, which also has the same problem as above. Even if the intermediate roll drive is used to reduce the diameter of the work roll, when rolling stainless steel, the advantage is that it has the middle roll twitch function, and it has the means to adjust the edge wave of the plate, but because of the large rolling pressure, the height of the roll system increases, The horizontal bending deformation in the middle of the frame window is twice as large as that of the four high mill under the same working conditions, which is not conducive to the stability of the roll system under rolling conditions. The six high mill is not suitable for the production of 200 series and 300 series stainless steel.
（3） Offset eight high mill
It belongs to the improved type of four high rolling mill, with two-layer roll system. It is composed of two backup rolls, two work rolls, two intermediate rolls arranged on one side of the work roll and two side auxiliary backup rolls. The backup roll is driven. Compared with the four high mill driven by backup roll, it overcomes the horizontal side bending of the work roll in the rolling process due to the small diameter of the work roll. The disadvantage is that, due to the asymmetry of the roll system configuration, the horizontal stiffness of the roll system is large when rolling to one side while it is poor when rolling to the other side. Although the roll system has no twitch function, it has a dynamic crown adjustment function, which is basically suitable for the rolling requirements of the three series of stainless steel, especially for the rolling of the 200 series and 300 series blooming.
（4） 12 high rolling mill
It belongs to the tower type roll system rolling mill and three layer roll system. It is composed of six backup rolls, four intermediate rolls and two work rolls, which are driven by four intermediate rolls. The roll system has strong stability and is suitable for stainless steel rolling, overcoming the horizontal side bending of the work roll. No matter which side the horizontal stiffness is the same, the roll system also has a dynamic adjustment function. However, due to the fact that the intermediate roll cannot be twitched, there is a lack of edge wave adjustment means for the plate surface. Therefore, the rolling of precision strip or wide plate surface is affected to some extent.
（5） Twenty high mill
It belongs to the tower roll mill and four layer roll system. It is composed of eight backup rolls, six two intermediate rolls, four one intermediate rolls and two work rolls, and is driven by four outer two intermediate rolls. The roll system has strong stability and is suitable for rolling stainless steel; There is no side bending when the work roll is rolled horizontally in any direction. The roll system has a variety of adjustment functions, such as dynamic adjustment, one intermediate roll twitching, etc. The plate shape adjustment means are rich. In the production of stainless steel reversible cold rolling, it can meet the requirements of rolling precision strips and plates with high surface standards, and can produce products for various purposes.
When selecting the type of stainless steel cold rolling mill, stainless steel cold rolling enterprises should integrate the main characteristics of the mill and the use of the products produced by the investor, so as to reasonably determine the type of machine, improve the cost performance ratio of equipment investment, ensure the proper selection of equipment, improve the output and quantity of production products, and achieve the best benefit of capital investment and equipment investment.