How To Improve The Service Life Of Sunken Rolls
The sinking roll device life from 7 to 10 days to the present 30 to 35 days. The main ways are as follows.
1. Sinking roll device under the tension of the strip drag, the roller does not turn or turn the situation is not good, resulting in the strip during the operation due to sliding with the roller surface is too large strip surface scratches caused by the need to replace the sink roller device. This is usually the case at the beginning of the sinking roll replacement. Analysis of the problem lies in the following areas.
(1) the assembly gap is too small and the relative position of the component assembly error, resulting in sunken roller device in the hot state of zinc liquid roll or resistance is too large, thus affecting its normal rotation. Solution: Develop a standardized control of the size of the standard, and in the assembly of strict implementation.
(2) the preheating temperature curve is too steep and uneven heating, resulting in sunken roller device under the action of thermal stress deformation is too large, resulting in poor roller rotation. Solution: adjust the preheating furnace temperature curve and heating method.
(3) due to the stability of the roller, the positioning roller is a solid roller, in the very thin plate or high-speed state, the roller rotation is poor, according to the calculation that reduce the roller radial load can reduce the friction torque at the journal, So that the roller rotates lightly. So we use a solid roller for the hollow roller way, this will greatly reduce the role of friction in the journal at the moment.
2. After the sinking roll device is running for some time, due to the serious wear and tear of the inner and outer bushings, it is necessary to replace the sinking roller device, and the analysis problem lies in the following aspects.
(1) inside and outside the shaft is widely used in the material for the G040 or G050, but this material in the zinc liquid in the high temperature, friction, corrosion state, the ultimate service life is generally only 7 to 10 days. Solution: the use of new high-alloy materials and the use of special processing technology to manufacture inside and outside the sleeve to ensure that its use in the zinc liquid 30 to 35 days, the wear from the original 5 ~ 10mm into control now in 1 ~ 2mm.
(2) inside and outside the sleeve structure is unreasonable, resulting in the use of abnormal wear or damage. Solution: change its structure to make its structure reasonable.
3. After the installation of the sinking roll device for a period of time, due to stabilization roller and positioning roller surface nodulation to the strip surface caused by indentation caused by the need to replace the sink roller device, the analysis is: to improve the adhesion of zinc in the strip surface, Modern hot galvanized often add a small amount of aluminum alloy to the zinc solution. However, in the process of galvanizing, these aluminum-zinc alloy will be attached to the roll surface, the formation of uneven nodulation. Solution: Spray a layer of special material on the sink roll, stabilizer roller and set roller surface and process the roller surface with special treatment. This material has the characteristics of no peeling, abrasion, zinc corrosion and no nodulation in the zinc solution. With this method, the life of the sinking roll device can be increased from 15 to 18 days to 40 to 50 days.