Annealing furnace is usually used to produce high-quality home appliance plate and automobile plate, generally including the following furnace sections: jet preheating section (JPF), radiant tube heating section (RTF), soaking section (SF), slow cooling section} SCS, rapid cooling section (RCS}, outlet section (ES), etc. The annealing furnace adopts advanced energy-saving technologies such as three-stage waste heat recovery (the first stage is used to preheat combustion supporting air, the second stage is used to preheat strip steel, and the third stage is used to generate superheated water), push-pull combustion system and its supporting on / off combustion control system, furnace composite lining, etc.

Precautions for annealing furnace operation

The steel structure of annealing furnace mainly includes shell support frame and driving equipment support frame (platform steel structure). Considering the potential thermal expansion and cold contraction of the shell, the supporting frame and platform steel structure of each section of the shell are independent of each other. The bottom roller chamber of each furnace section is installed in place first, and four benchmark pillars are welded based on their own four corner pillars; Then weld the left and right integral end plates. The operation side and the transmission side are welded and installed from bottom to top by several independently manufactured side plates respectively, and then install the top roller chamber. The top roller chamber also has four reference columns, which are positioned and welded with the furnace body and four from the standard columns to complete the manufacturing and installation of the annealing furnace shell. A widened platform is installed on the transmission side to store the furnace top cover. The principle is simple!

According to the working principle of the slow cooling section, the preliminary analysis is that the channel steel cracking is caused by the inconsistency of thermal expansion, and the negative pressure generated by the circulation cooling suction of the circulating fan will bring the right gas into the furnace, which makes the oxygen content in this section higher, and the furnace condition is stable when the steel grade e7j is not changed; Once the steel specifications are changed and the temperature changes frequently, the cracking will be further deteriorated and the furnace condition is difficult to maintain stable.

When the steel grade is switched, the temperature difference between the inlet and outlet air in the slow cooling section of the hot dip galvanizing unit is usually required to be about 200 K. considering the gap between the cooling air box and the furnace shell, the high temperature circulating gas will exchange heat at this gap; On the other hand, if = steel and channel steel on the air duct frame are welded with the steel structure of the furnace shell, the heat difference between the normal temperature air outside the furnace and the high temperature gas inside the furnace will produce a thermal gradient on the corresponding channel steel; or because the expansion and rigidity of stainless steel expansion n can not meet the temperature difference deformation requirements of the air duct, it will also cause the channel steel to crack.