The steel rolling mill rolls include work rolls and backup rolls, which are critical parts of the rolling mill. In the production of hot-rolled steel bars, the rolls are always in direct contact with the red-hot steel slab, which consumes a lot. Therefore, prolonging the service life of steel rolling mill rolls and reducing roll consumption are issues of great concern to both rolling mill manufacturers and users. So, how can we prolong the service life of steel bar rolling mill rolls?
There are many types of roll damage in steel bar mills, including mechanical wear, chemical wear, thermal wear, cracks in the roll, peeling of the registration, and so on. For the common types of rolling mill roll damage, you can refer to the article "The 4 Most Common Failures of Hot Rolling Mill Rolls", so I won’t go into details here.
Next, let's focus on the measures to extend the service life of the rolls.
The hot rolls work in an environment of 700~800C for a long time, in direct contact with the hot steel billet, and bear strong rolling force. At the same time, the surface of the steel bar rolling mill rolls also bears the strong wear of the rolled material, is repeatedly heated by the hot-rolled material and cooled by cooling water, and is subjected to thermal fatigue caused by large temperature changes. Therefore, hot-rolled materials are required to have the characteristics of high hardenability, low thermal expansion coefficient, high thermal conductivity, high-temperature yield strength, and high oxidation resistance.
Cracked rolls should be replaced in time for grinding to ensure a moderate amount of grinding to eliminate residual cracks.
In order to reduce or eliminate internal stress, the work roll should be annealed for stress relief after one period of use, or the ground roll should be immersed in oil at a specific temperature for storage.
Reasonable roll shape configuration, uniform contact stress between rolls, maintain appropriate and uniform wear, and use the driving effect of wear to effectively eliminate roll peeling.
To ensure the normal input of cooling water, the management of the cooling nozzles of the rolls must be strengthened during use to ensure that the nozzles and filter screens are not blocked and the water volume is sufficient to ensure that the temperature of the rolls is controlled within the normal range; in the production of hot-rolled strip steel Rolling lubrication technology can also be applied in the process. The practice has proved that rolling lubrication can reduce the wear of the roll, reduce the rolling force and rolling torque, relieve the thermal fatigue of the roll, and improve the stress state during rolling: The application of online grinding roll technology and work The rolls are traversed to reduce the wear of the rolling plate, extend the rolling kilometers of the strip, and reduce the number of roll changes.
Roller damage is caused by the interaction and influence of multiple factors, and its damage forms are diverse. Although roll damage cannot be completely avoided in actual work, we can propose corresponding solutions for specific damage forms: the material selection of rolls can also be considered according to the use environment of the roll to ensure that the roll can withstand large temperature changes The effect of thermal fatigue; it is also possible to reduce the wear of the rolling plate by rationally arranging the roll changing cycle, rationally arranging cooling water and rolling lubrication, and applying online grinding roll technology.
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