Roller for galvanized aluminum sheet and preparation method thereof

Abstract

Disclosed by the present invention are a roller used for galvanized aluminium sheet and a preparation method therefor. According to the present invention, the content of retained austenite is regulated as 8%-15%, and the rigidity is 93-95HSD. The raw materials are placed in a medium-frequency induction furnace to prepare an alloy liquid, and a semi-finished product is cast under a low temperature; a finished product is obtained after heat treatment, thermal refining, quenching treatment, cold treatment, tempering treatment and final fine grinding, the cold treatment temperature being -30 to 5 degrees centigrade. The austenite phase area is enlarged while elements such as Ni and Mn are added, thus a critical point of retained austenite meeting the manufacturing technique is found. That is, the rigidity regulation not only satisfies the rolling force, but also prevents the situation that the roller cannot be used at a minimum diameter due to low rolling rigidity. Meanwhile, the combination of different alloy components and different technologies not only improves the corrosion resistance of the galvanized aluminium roller but also enables the austenite to be stabilized in different working temperatures, thereby prolonging the service life of the roller while improving the surface quality.

Description

technical field [0001] The invention relates to a roll for galvanized aluminum sheet and a preparation method thereof. Background technique [0002] Rolls are required to be wear-resistant, and hardness has become a daily control index. However, hardness and wear resistance are not unconditionally unified, so when selecting a roll, in addition to hardness, it also depends on its composition, production method, organizational structure, other properties and residual stress. Therefore, when selecting the hardness of the roll, it also depends on the conditions of the rolling mill, the rolling conditions, the variety of the rolled piece and the operating experience. The demand for aluminum-zinc sheets is increasing, and the current production volume cannot meet the overall demand. The reason is that the work rolls for rolling aluminum-zinc sheets have a large area of ​​peeling, which cannot fully meet the production requirements, resulting in a reduction in output. [0003] We...

AI Technical Summary

Problems solved by technology

Therefore, when selecting the hardness of the roll, it also depends on the conditions of the rolling mill, the rolling conditions, the variety of the rolled piece and the operating experience. The demand for aluminum-zinc sheets is increasing, and the current production volume cannot meet the overall demand. The reason is that the work rolls for rolling aluminum-zinc sheets have a large area of ​​peeling, which cannot fully meet the production requirements, resulting in a reduction in output

[0003] We analyze the reasons for spalling: 1. Aluminum and zinc are corrosive to ordinary rolls. Rolls with zinc, aluminum or zinc-aluminum alloy attached will produce hydrogen due to chemical reactions when zinc or aluminum encounters water, and hydrogen will penetrate into the roll. After aggregation, hydrogen molecules are formed, and volume expansion leads to hydrogen embrittlement, which seems to peel off the surface of the roll

2. Selection of hardness. Generally, the hardness of the roll is required to be 95-98HSD, so the working roll must reduce the existence of retained austenite by adding cryogenic treatment, enhance the hardness of the roll, and avoid the peeling problem caused by the retained austenite; However, the higher the yield strength, the greater the susceptibility to hydrogen embrittlement, and the inclusion of sulfides and the untempered martensite structure are prone to hydrogen embrittlement.

[0005] However, although the above method has alleviated the problem of hydrogen embrittlement, it has been shown through tests that the corrosion of rolls attached with zinc, aluminum or zinc-aluminum alloys in a humid environment is still the main factor affecting the life of the rolls, and the service life of the rolls has not been significantly improved. , the rolls are frequently ground and repaired, so that the size of the rolls is quickly smaller than the specified value, and the scrapping time is shortened. Even, as the temperature changes during use, the retained austenite is not stable, and the local hydrogen embrittlement problem will still occur randomly