Trolley type annealing furnace is usually used for the production of high quality home appliance panels and automobile panels.It generally includes the following sections:jet preheating section(JPF),radiating tube heating section(RTF),equiheating section(SF),slow cooling section(SCS),fast cooling section(Rcs),exit section(ES),etc.The latest trolley annealing furnace adopts advanced energy-saving technologies such as three-stage waste heat recovery(first-stage waste heat recovery is used for preheating combustion-supporting air,second-stage waste heat recovery is used for preheating strip steel,and third-stage waste heat recovery produces superhot water),push-pull combustion system and matching ON/OFF combustion control system,furnace compound lining and so ON.

The steel structure of the trolley annealing furnace mainly includes the supporting frame of the furnace shell and the supporting frame of the driving equipment(the platform steel structure).Considering the potential heat expansion and cold contraction of the furnace shell,the supporting frame of each section of the furnace shell and the steel structure of the platform are independent of each other.The bottom roller chamber of each furnace section is first installed and installed,and the four benchmark columns are welded according to their own four corners.Weld the left and right integral end plates again.And operation side and transmission side side panel of each manufactured by several independent from the bottom in the welding installation,the installation of roof top roller roller room also has four benchmark pillar,and the furnace body from four prospective life column can complete the positioning welding bogie hearth furnace annealing furnace shell produce a few a wider platform installation on the drive side,to hold top cover,principles!_

According to the working principle of slow cooling section,the preliminary analysis is that the inconsistency of thermal expansion in the section leads to the crack of channel steel,and the negative pressure generated by the circulating cooling and suction action of the circulating fan will load the air belt into the furnace,so that the oxygen content of the section is high and the furnace condition is stable when the steel specification E7J is not changed.However,once the steel specifications are changed and the temperature changes frequently,the cracking will be further deteriorated and the furnace conditions will be difficult to maintain stability

When the steel specifications are switched,the temperature difference between the inlet and outlet air of the slow cooling section of the hot-dip galvanizing unit is generally required to be about 200K.Considering the gap between the cooling bellows and the furnace shell on one side,the high-temperature circulating gas will be exchanged at this gap.On the other hand,since the i-F=steel and channel steel on the duct frame are welded together with the steel structure of the furnace shell,the thermal difference between the ambient 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 stiffness of stainless steel expansion N is difficult to meet the deformation requirements of wind pipe temperature difference,it will also lead to the channel steel tensile crack.