Problems and solutions related to emulsion in rolling production
March 28, 2022
The modern cold rolling process is pursuing the development of large pressure, high speed and continuous direction, and the lubrication and cooling effect of the emulsion cannot be ignored. With the competition in the market, process lubrication plays an important role in saving energy and reducing consumption and improving the surface quality of products. The lubrication and cooling effect of emulsion is the technical core of cold rolling lubrication process. Understanding the influencing factors of the performance parameters of emulsion and controlling it reasonably can improve its rolling lubrication effect and ensure smooth rolling.
Problems and solutions related to emulsion in rolling production 1. Thermal scratches Too thin oil film thickness or too little oil film is the main reason for thermal scratches. Its solution: 1) Increase the concentration of the emulsion; 2) Increase the temperature of the emulsion; 3) Increase the injection volume (flow) of the emulsion; 4) Use rolls with larger diameters; 5) Reduce the roughness of the roll surface; 6) Increase the iron content in the emulsion (ie, open the magnetic bar less). 2. Slip Contrary to the phenomenon of thermal scratching, if the thickness of the oil film is too large, or the range of fluid lubrication increases, and the friction coefficient decreases below a certain bond, slippage will occur. Its solution: 1) Reduce the concentration of the emulsion; 2) Reduce the temperature of the emulsion; 3) Reduce the content of iron powder in the emulsion (such as open magnetic rod filter, oil sprinkler, etc.); 4) Increase the surface roughness of the roll. 3. The board surface is black Among the ratios of oil content and iron content on the surface of the steel sheet after rolling, the higher iron content ratio causes the blackening of the plate surface. Its solution: 1) Increase the temperature and concentration of the emulsion; 2) Reduce the iron content in the emulsion; 3) Reduce the surface roughness of the roll. 4. Vibration In terms of lubrication, it is caused by "lubricity scars", that is, the rolling oil involved in the roll gap fails to reach a uniform state, and the friction coefficient of the uneven part is quite different from that of other places. Its solution: 1) Increase the temperature of the emulsion; 2) Increase the surface roughness of the roll. 5. Rust and emulsion spots Due to the poor shape of the strip, the emulsion carried out is involved in the steel coil, and the water on the surface of the strip is not completely removed, both of which may cause emulsion spots. High ambient air temperature or high concentration of hydrochloric acid will cause point rust to occur. Its solution: 1) Increase the amount of air purging; 2) Increase the temperature of the emulsion; 3) Increase the concentration of the emulsion; 4) Improve the working environment around the rolling.
6. Rolling force rises If the rolling reduction is too large and the material is hard, it is easy to cause the rolling force to rise. Its solution: 1) Appropriately increase the temperature and concentration of the emulsion; 2) Reduce the surface roughness of the roll, and use a small roll diameter for rolling. The above-mentioned first six problems can also be solved by improving the variety of rolling oil.
