Judian is a manufacturer of rolling mills and has a lot of experience in equipment. Today we are going to discuss some issues related to rolling steel production.
The reduction amount of the rolling group is very small, and the main task is to ensure the excellent surface quality and dimensional accuracy of the finished profiles.
Therefore, the rolling mill requires the stand and the roll to have excellent wear resistance and anti-chipping and spalling properties and also requires the roll to have a certain thermal fatigue resistance.
When rolling steel, the distance between two roll rings on the same pass is called the roll gap. The function of the roll gap is to make the roll ring or the upper and lower rolls not rub against each other; the second is to adjust the height of the pass, so as to avoid the excessive size of the end face of the product caused by the roll jump and the wear of the pass.
During the rolling process, the various parts of the rolling mill are elastically deformed by the rolling force, such as the height expansion of the stand window, the bending of the roll, the compression of the screw and the bearing.
These elastic deformations are finally reflected in the increase of the gap between the two rolls, and the phenomenon of this increase in the roll gap during rolling is called roll jump.
The total value of the increase in the roll gap is called the roll jump value. The better the rigidity of the rolling mill, the smaller the roll jump value. The greater the deformation resistance of the rolled piece, the greater the roll jump value.
The basis for judging the quality of roll gap adjustment is: smooth rolling process, qualified rolling stock size, normal rolling stock shape and even distribution of reduction.
The specific operations of roll gap adjustment include:
(1) Roll gap adjustment to compensate for wear after rolling a certain amount;
(2) According to the size of the rolled piece, the change of the steel material of the rolled steel and the change of the process parameters, the roll gap is flexibly adjusted.
Run the rolling mill under test at the crawling speed, hold the round steel bars of the corresponding size, press a round steel bar on the roll ring on the working side and the rotating side, and measure the indentation height of the two round steel bars. And compare it with the set value of the roll gap, and adjust the pressing repeatedly until the measured indentation height is equal to the set value of the roll gap.
The water pressure of the roll cooling water is generally controlled at 0.3~0.6Mpa.
If the pressure is too high, it is easy for the water to splash out from the roller surface, and the amount of cooling water is insufficient, which causes waste at the same time.
If the water pressure is too low, the cooling effect of the roll surface is not good, and it is easy to cause cracks, singing, or even broken roll accidents on the surface of the roll.
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