Research on the forging heating process specification of heavy forgings

Large forging is also a kind of more common forging, the following article is mainly to tell you the content of the long shaft large forging heating process specifications.

Large forgings are generally used in the drive shaft, is the key and core parts of machinery and equipment, is the foundation of manufacturing major equipment, quality requirements are very strict. The production process of shaft heavy forgings is heating before forging, forging and heat treatment after forging. Because the production of large forgings is mostly single production, the scrap of forgings will cause huge economic losses and cause the delay of construction period. Therefore, it is necessary to make reasonable heating specifications to ensure the safety of ingot heating and reduce heating time to achieve the purpose of energy saving.

Specific research contents and conclusions are as follows:

(1) When the furnace is installed at room temperature, the maximum heating capacity of the furnace can be used for heating the ingot. The stress field and temperature field of ingot heating were obtained by simulation. The core stress of the ingot is three-direction tensile stress, and the axial stress is the largest. The peak values of axial stress and surface core temperature difference appear at low temperature and phase transformation of ingot core. From the perspective of rapid heating, the optimization parameters of heating specification are: the insulation temperature of rudder ingot during phase transition is 850℃, the insulation time of phase transition is 1 hour, and the forging insulation temperature is 1235℃. The insulation temperature of propeller shaft ingot during phase transition period is 850℃, the insulation time of phase transition period is 0.8 hours, and the forging insulation temperature is 1220℃.

(2) In the case of high temperature furnace loading, the heating speed of ingot is obviously accelerated in the low temperature period, but the stress in the core also rises greatly, that is, the heating time can be effectively reduced by high temperature furnace loading, but the maximum furnace loading temperature must be controlled. The holding time at the furnace loading temperature is 2 hours for the tiller ingot and 1.5 hours for the propeller shaft, and the remaining time is the same as that at the low temperature.



(3) The subsequent heating times are different from the previous heating times. Because the internal temperature of the forging is high, and the surface temperature is low, so when the furnace temperature reaches the forging heat preservation temperature, the inner surface temperature difference of the forging is not large, so the heating needs to choose a smaller forging heat preservation temperature,1220℃. When the forging length is longer than the heating furnace length, the forging part without the furnace will have a great influence on the temperature of the forgings near the furnace door in the furnace. In order to reduce the heating time, it is necessary to increase the length of the furnace.

this is large forgings produced by Tongxin precision forging company