Application Method of Well Carburizing Furnace

As the outside of the carburizing furnace tank is close to the electric heating element, the temperature is relatively high, up to 950-l000 degrees, so the carburizing furnace tank is required to have good oxidation resistance; The inner side of the carburizing furnace tank is in the carburizing atmosphere, which requires the carburizing furnace tank to have good carburizing resistance. At the same time, due to the large load of the carburizing furnace tank, it is also required that the carburizing furnace tank has high high temperature strength.

The surface outside the carburizing furnace tank will be oxidized and peeled, which will lead to cracking, and the main form of failure is gas leakage of the carburizing furnace tank. Casting defects have a great impact on the service life of carburizing furnace tank, and there are often more opportunities for oxidation and cracking at the defects. After slight cracking, the carburizing furnace tank was used soon after repair welding, and was damaged quickly, which was mainly due to the decline of welding performance after oxidation and carburization.

Sometimes a ring crack occurs below the mouth of the carburizing furnace, which is related to the structure of the carburizing furnace and the complex stress in this area. From the structure, it can be seen that the ring crack area is the transition zone between the high temperature area in the tank and the low temperature area at the upper carburizing furnace mouth. Therefore, under the effect of different temperatures at the upper and lower parts, the thermal stress in this area is large. In addition, this area is just at the part where the bottom of the sealing ring at the furnace mouth is connected with the tank wall, which is at the section change part. Due to the superposition of thermal stress and load stress, and the bottom of the sealing ring is the supporting point of the whole carburizing furnace tank, the stress at this part is large during operation. Moreover, this is the hot spot of the casting, which is more likely to have casting defects, so there are annular cracks perpendicular to the stress.

Comparison of service life of carburizing furnace tank, Cr18Ni25Si2 The furnace pot of Cr25Ni20 steel has a long service life, more than 3 times that of Cr18Mn12Si2N steel.