Relationship between Daily Working Efficiency of Rolling Mill and Ambient Humidity and Temperature

It has been proved by practice that environmental factors are also included in many factors affecting the daily work efficiency of the rolling mill, mainly the humidity and temperature of the environment. Therefore, in order to improve the working efficiency of the rolling mill, the narrow outlet of the heating furnace has strict requirements for humidity. In the case of no tapping, closing the furnace door can reduce air consumption and heat transfer, and reduce the cost of coal or gas. 

If the humidity around the rolling mill is too high, it will lead to the increase of the partial pressure of water and gas in the heating furnace of the rolling mill and the decrease of the average driving force in the furnace. In order to maintain the same heating capacity, it is necessary to increase the length and width of the heating furnace at this time, and then increase the investment cost.

For the same kind of billet, the suitable relative humidity values are different for different types of heating furnaces selected in the rolling process. If the rolling mill uses walking beam furnace, because the residence time of the billet in the furnace is short, it requires the large driving force to improve the heating rate. Generally, the partial pressure of the outlet gas water vapor should be lower than half of the surface water vapor pressure of the outlet material; if the rolling mill is replaced by the regenerative heating furnace, the partial pressure of the outlet gas water vapor is generally about 60% of the surface water vapor pressure of the billet.

For some rolling mills, certain air speed is required. Therefore, the relationship between gas volume and relative humidity should be considered in the construction of heating furnace. In order to meet the requirements of larger gas velocity, more air can be used to reduce the relative humidity value, enhance the heating rate of billet and reduce the high-temperature loss.

The reason why the temperature of the rolling mill inlet should be controlled is to strengthen the ability of the billet to reach the variable rolling quickly. Generally, the inlet temperature of the rolling mill should be kept within the suitable temperature range allowed by the billet, and the optimal temperature is 1150 ℃.

For the same type of billet, the temperature at the same pass inlet is allowed to vary with the heating furnace. For the same kind of billet, different quenching and heating temperature and holding time will also have certain impact, so in the actual rolling process, we must adjust the temperature of the rolling mill according to different requirements.