The Stability Transformation Of The Roller System Of Baoti Group's Wide And Heavy Plate Rolling Mill

The Stability Transformation Of The Roller System of Baoti Group's Wide and Heavy Plate Rolling Mill Has Been Successfully Revitalized

After nearly two years of observation and verification, the stability transformation of the roller system of Baotai Group's 3300mm wide and thick plate rolling mill completed in October 2020 was very successful, and the shape of the rolled sheet has been greatly improved, giving this wide and thick plate rolling mill with nearly a hundred years of history a new vitality and creating huge economic benefits for the company.

The 3300mm wide and thick plate rolling mill is a second-hand equipment bought from Germany at scrap steel prices in the 1990s. It has been used for the production of medium and thick plates of steel and composite plates since it was installed and put into operation.In recent years, as the main rolling equipment, a large number of titanium and titanium alloy sheets have been processed for the company. Due to the old rolling mill's low accuracy, the shape and yield of the rolled sheet are quite different from that of the 1200mm rolling mill. Due to quality problems, the increase in production has been restricted. The company had to spend a lot of money on a new 1850mm rolling mill to solve the problems of wide-format sheet rolling quality and production capacity.                     

In March 2020, repeated damage to the pressure sensor of the 3300mm rolling mill affected production. Since ABB quoted 600,000 yuan for each pressure sensor, but the service life was only three months, repeated damage caused a lot of economic losses.The wide and heavy plate company reported to the asset equipment department of the competent equipment department to organize experts to diagnose the faults of the rolling mill and sensors.After on-site observation and analysis, Technical director Zhang Wenzheng found that the force condition of the pressure sensor is not good when it is working. In addition to bearing the rolling pressure in the vertical direction, the instability of the working roller during rolling causes the pressure sensor to be repeatedly forced in the horizontal direction, resulting in fatigue fracture within a certain period of time.

After the reason was found, the asset equipment Department of Baotai Group and the equipment maintenance team of the wide and heavy plate company consulted the information together to formulate the maintenance plan. In accordance with the principle of roll stability of the four-roll rolling mill driven by the working roller in the relevant professional book, with reference to the working roller of the 1200mm rolling mill, the stability plan of the 3300mm rolling mill working roller system was designed. Through accurate measurement of the window size of the rolling mill frame, the liner was manually polished and the bearing box was repeatedly tested. After nearly three months of hard work, the adjustment of the stability of the roller system was finally completed in October 2020.In the process of reversible rolling, the lateral gap of the working roller has been eliminated, the working roller has not swayed horizontally in the past, and the force of the pressure sensor has been improved. After two years of operation, it has not been damaged; the working roller is stable during rolling and the seam of the roller is locked, avoiding the intersection of the axis of the working roller to produce plate waves and the transverse thickness and size are extremely poor. The working accuracy of the rolling mill has been qualitatively improved compared to the 30 years since the rolling mill was installed and put into operation. The shape of the rolled sheet has been greatly improved, which reduces the pressure for subsequent straightening and grinding processes, and greatly improves the quality and output of the sheet.

Through the analysis of the current technical situation of the 3300mm mill, Zhang Wenzheng, director of the asset department of Baoti Group, said that the adjustment of the stability system of the work roll system has improved the working accuracy of the mill, changed the situation that the broad and heavy plate mill can only "eat coarse grain" and "do rough work", can only produce low products, also the product quality with production capacity have been greatly improved. Combined with nearly 10 years clemency board rolling line constantly input, including machine before extending roller table, and high pressure water descaling equipment, stepper gas heating furnace, roller hearth type electric heating furnace, and the finishing line segment type wide under pressure straightening machine, horizontal pickling line and so on all the production equipment, the entire rolling line equipment has reached the domestic advanced level.