In order to strengthen the rolling mill billets to achieve deformation rolling quickly, the inlet temperature of the rolling mill should be kept within the suitable temperature range allowed by the steel billet, and the temperature is 1150 degrees. The purpose of heating the billet is to achieve the thermal characteristics required for rolling. It should be noted that physical and chemical changes such as discoloration, decomposition, melting, and deformation of the billet should be avoided.
For billets of the same type, it is allowed to import in the same pass, and the temperature varies with different heating furnaces. For the same billet, different quenching heating temperatures and holding times will also affect it. Generally, in the regenerative heating furnace, since the steel billet is stepped from the low-temperature zone to the high-temperature zone by the steel pusher, the temperature of the steel outlet is the highest, and the steel billet is heated from both sides, and the steel billet does not need to be heated. Turning can make the steel billet heated evenly, with high speed and a short time.
The tapping hole of the heating furnace of the rolling mill billets has strict requirements for humidity. When there is no steel, the furnace door can be closed to reduce air consumption and heat transfer, which can reduce the cost of coal or gas. If the surrounding humidity is relatively high, the partial pressure of water vapor in the heating furnace of the rolling mill will increase, which will reduce the average driving force in the furnace. In order to maintain the same heating capacity, the length and width of the heating furnace need to be increased at this time, which immediately increases the investment cost. . When the steel billet is rolled, there are corner and surface cracks, which seriously affect the surface quality of the billet.
For the same billet, the type of heating furnace selected is also different, and the appropriate relative humidity value is also different. For example, for a walking heating furnace, since the residence time of the billet in the heating furnace is very short, a large driving force is required to increase the heating rate. Generally, the water vapor partial pressure of the outlet gas needs to be lower than half of the water vapor pressure on the surface of the outlet material. ; For regenerative heating furnaces, the partial pressure of water vapor in the outlet gas is generally about 60% of the water vapor pressure on the billet surface.
If the temperature of the heating furnace increases, the heat loss will be large. If the temperature is lowered and the relative humidity is high, the humid air may precipitate water droplets in the equipment and pipelines behind the ingot heating furnace, thus destroying the normal operation of the heating furnace. The temperature change inside the rolling mill billets, when it is heated in the furnace, is an important parameter.