New roll production process

Rolls, including work rolls and support rolls, are one of the key parts of the mill, installed in the mill. In the hot strip production, roll consumption is very large, especially the work roll, it is always in direct contact with the red hot steel billet. Therefore, to find out the causes of damage to the rolls and make corresponding measures to improve roll life, reduce roll consumption, is the mill, manufacturers and users are very concerned about the problem. In the actual production process, the destruction of rolls in the form of roll wear, roll cracks roll spalling and roll fracture. Roll failure reasons are as follows:

Roll wear
Hot rolls work in the environment for a long time, in direct contact with the hot billet, bearing a strong rolling force, while the surface also has to withstand strong wear and tear of the rolled material, and repeatedly by the hot rolled material heating and cooling water cooling, subjected to temperature changes in thermal fatigue effect. Therefore, the requirements of hot roll rolling material with high hardenability, low coefficient of thermal expansion, high thermal conductivity and high yield strength at high temperatures and high oxidation resistance. Cracked rolls should be replaced in time for grinding, to ensure its moderate amount of grinding to eliminate residual cracks. In order to reduce or eliminate internal stress, the work roll in the use of a cycle should be carried out after a stress relief annealing, or grinding rolls immersed in a certain temperature with a certain temperature of the oil preservation. Reasonable roll roll configuration, uniform contact stress between the rolls, to maintain a moderate amount of uniform wear and tear, the use of wear and tear to promote the role of the effective elimination of roll spalling. From the aspect of rolling process. To ensure the normal input of cooling water, in the process of use must strengthen the management of roll cooling nozzles, to ensure that the nozzles and filters are not clogged, the amount of water is sufficient to ensure that the temperature of the rolls is controlled within the normal range; in the production of hot rolled strip steel can also be applied to the rolling lubrication technology, practice has proved that rolling lubrication can reduce the wear and tear of the rolls, reduce the rolling force and the rolling torque, alleviate the thermal fatigue of the rollers, and improve the rolling The stress state; the application of online grinding roll technology and work roll traverse to reduce roll wear, extend the rolling kilometers of steel strip, reduce the number of times to change the roll.

Roll damage is caused by a variety of factors interacting with and influencing each other, and it is damaged in various forms. Although in practice the roll damage can not be completely avoided, but we can target specific forms of damage, the corresponding solutions; can also be based on the use of the roll environment to consider the roll material selection, to ensure that the roll can withstand temperature changes in thermal fatigue; can also be reasonably arranged for the replacement of the roll cycle, a reasonable arrangement of cooling water and rolling lubrication and other technological means and the application of on-line grinding technology to reduce roll wear.
The wear and tear of the rolls.
To sum up, roll fracture and deep cracks on the working surface are irreversible losses, the reasons are very many, through strict control of material composition, forging process, reasonable processing, reasonable arrangement of heat treatment, and strictly in accordance with the rules for the use of rolls using rolls, you can effectively reduce the frequency of roll cracking.

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