Radiant tubes U type by centrifugal casting

 

U type  radiant tube

The structure of U type radiant tube is mainly composed of two sections of centrifugal casting main pipe and 180° elbow, flange and fixed plate. It is installed in the furnace in conjunction with the burner burner and other structures.

After the burner is ignited, it burns in the tube, and the exhaust gas produced by the combustion is discharged from the other end of the tube. High-efficiency radiant tubes often have waste heat recovery devices, which can not only improve the temperature distribution of the radiant tube wall surface, but also improve the thermal efficiency.

 

The straight section of the U-shaped radiant tube adopts the high-temperature centrifugal casting pitted tube, and the elbow adopts the precision casting process. The heat energy is provided by natural gas or coke oven gas combustion in the radiant tube, and the strip steel running at a uniform speed is rapidly and uniformly heated from normal temperature to about 1000 degrees by means of radiation heat transfer outside the radiant tube, and the strip steel is annealed.

 

The key component of the U-shaped radiant tube is the tube body, which radiates the heat released by the combustion of the fuel to the heated material. Because the surface of the tube body is in direct contact with the combustion flame and high-temperature flue gas, the working environment is harsh. For the radiant tube made of metallic materials, the material will fail due to local burning and oxidation for a long time; if it is along the length of the tube body There is a large temperature difference, and the tube body needs to withstand a large thermal stress, which will directly affect the length of the life of the tube body; coupled with the impact of the airflow during combustion, certain vibrations will also occur. Therefore, the material of the radiant tube must meet the following conditions: 1) high temperature resistance; 2) high surface blackness; 3) high thermal conductivity; 4) high structural strength and good air tightness; Under the action of working temperature and self-load, it has good anti-oxidation performance, and can withstand sufficient high temperature creep and failure strength; 6) small thermal expansion coefficient; 7) low cost, etc.

 

Most of the radiant tubes produced by HEXIN are made of heat-resistant steel, and the temperature range is around 900-1000℃. Its processing method is usually made by rolling, extruding steel pipe or centrifugal casting. In theory, the higher use temperature of various heat-resistant steels will vary with the use conditions and controllable atmosphere. In the actual production process, a reasonable radiant tube material should be selected according to the process conditions such as the furnace temperature, furnace atmosphere, and the type of materials to be heated.