hot rolling lubrication oil supply method
Hot rolling refers to the processing of ferrous and non-ferrous metals into shapes or shapes at temperatures usually above the recrystallization temperature.Because during hot rolling, shear and compression of steel are generated at the same time, it has higher requirements for the lubrication oil.
Correct choice of lubricating oil plays an important role in the hot rolling process. The lubricating oil in the hot rolling process has two main functions. One is to reduce friction between the rolling parts, reduce the surface pressure between them, and the other is to reduce adhesion and wear on the rolling surface. In hot rolling, friction and deformation are generated at the same time, so it will produce a certain lubricating effect.
In the hot rolling process, the effectiveness of lubricants is directly related to the quality of the entering steel billet, the performance of rolling mill and the size of rolling force. The quality of the billet affects the fluidity of the lubricant on the rolling surface, and the performance of the rolling mill and the rolling force determine the amount of lubricant injected and the pressure in the lubricating system.
The lubricant used in the hot rolling process should meet the following requirements:
1. The lubricating oil should have good thermal stability, oxidation stability and shear stability, and have good heat conduction performance. It is formed with rolling body and rolling oxide film;
2. The lubricating oil should have good anti-wear performance, viscosity and film strength;
3. The lubricating oil should have good adhesion to the hot rolled surface, so that it can form a film protected by rolling body;
4. The lubricating oil should be able to form a uniform lubricating film on the rolling surface in a wide temperature range, thus avoiding the phenomenon of dry friction in a certain temperature range;
5. The lubricating oil should be non-polluting and easy to clean up.
The oil supply method of hot rolling process should be based on the characteristics of hot rolling process and the actual situation of rolling mill to determine. Generally, there are three main oil supply methods: direct spray supply method, weir pool supply method and pinhole orifice supply method.
The direct spray supply method is to inject the lubricating oil directly into the hot rolled parts by oil nozzle or air pressure. The oil nozzle is arranged at the entrance of the rolling mill and above the roll surface. The oil can be injected directly into the roll gap with hollow orifice, grooved nozzle and dosing nozzle.
The weir pool supply method is to use a liquid pool upstream of the roll. The lubricant is supplied to the roll surface by means of a weir plate, and then the lubricant droplets are taken away by the layer of rolling stock. The advantage of this supply method is that it does not require a lubricating system and is relatively simple.
The pinhole orifice supply method is to use the gap between the upper and lower rolls to force a certain pressure of lubricating oil to form a fogging film on the surface of the roll. This method is suitable for small mills rolling large-diameter materials.
The lubricating oil used in the hot rolling process should be selected according to the characteristics of the hot rolled material and the requirements of the rolling process. Higher requirements should be placed on the performance of the lubricant to ensure the normal operation of the rolling process. The oil supply method should be based on the characteristics of the process and the actual conditions of the rolling mill to determine the most appropriate oil supply methods.
