The number of radiant tubes used in heating furnace is large and the price is expensive. For example, there are 128 radiant tubes used in a annealing furnace, and the price of each one is 37,000 yuan. If the service life of each one is increased by 0.5 ~ 1 year, great economic benefits will be generated. Therefore, how to improve the service life of radiation tube has a high research value. The main factors that affect the service life of the radiant tube are the material, structure and manufacturing process of the radiant tube, combustion atmosphere in the radiant tube, installation structure and maintenance, uniformity of surface temperature distribution of the radiant tube, production technology and operating level, etc.

The commonly used u-shaped or w-shaped radiation tube is of relatively large mass, and it is easy to be damaged by bending fatigue and creep deformation under the joint action of alternating thermal stress and its own mass. In order to reduce the deformation of the radiant tube, a fixed support structure integrated with the radiant tube is arranged at each elbow, which is supported on the furnace wall during installation. In order to adapt to the thermal expansion and cold shrinkage deformation of the radiation tube, an expansion joint is set between the outlet on the side of the burner and the furnace cover. At the same time, the fixed support at the elbow of the radiation tube is changed to floating support, which further reduces the generation of cracks. The evolution route to improve the service life of radiation tube is: flexible evolution route: rigid body system → single hinge system → multi-hinge system → flexible system → field connection system. According to this evolutionary route, the evolution process of improving the service life of the radiation tube is as follows: the radiation tube is in the stage of multi-hinge system, which can further improve the flexibility of the radiation tube and make it a flexible system, and then evolve to the field connection system. For example, the magnetic suspension principle can be used to make the radiation tube suspended.