PRODUCT CATEGORIES

Vacuum Heat Treatment Furnace

Vacuum Sintering Furnace

Vacuum Brazing Furnace

Transmission Gear Shaft Vacuum Heat Treatment

The transmission gear shaft is an important part of the automobile transmission system. In the processing technology of gear shaft, heat treatment is a very important link, and the selection of heat treatment process greatly affects the quality of the final product.

The traditional gear shaft heat treatment process relies on atmospheric carburizing, oil quenching, tempering and other processes to obtain parts that meet the design requirements, but the heat treatment equipment takes a long time to start and stop the furnace. The parts of this heat treatment method often need to be cleaned and shot blasted to remove the residual grease and oxide scale after heat treatment. The working environment of employees is poor, which is inconvenient to use and greatly increases the production cost and cycle of parts.

Advantages of vacuum treatment over traditional treatment:

After the continuous furnace heat treatment parts are released, there are oxidized film and grease residue; while the carburizing of the vacuum production line is carried out in a vacuum environment, and gas quenching is used. There is no oxidation and no quenching oil in the whole process. Therefore, the surface of the parts is smooth and clean after being released from the oven, and there is no oxidized film , which make them look gold.

The metallographic structure has no intergranular oxidation, and the surface of the parts has good fatigue resistance. The non-martensitic structure produced by the continuous furnace is often between 0.02 and 0.025mm, and the vacuum heat treatment parts have almost no non-martensitic structure and internal oxidation.

Vacuum furnace parts have less thermal deformation than continuous furnace parts. The vacuum furnace adopts gas quenching. There is only convection cooling process in the whole process, and the heat transfer coefficient remains unchanged, while the oil quenching cooling process has three stages: film boiling, bubble boiling and convection, and the heat transfer coefficient is different in each stage.

Short process times and high energy efficiency to produce identical parts. The process is flexible and adjustable. If the vacuum furnace wants to achieve different infiltration layers, it is only necessary to adjust the gas flow and time in a single process. There is no need to wait for the continuous furnace to wait for an empty furnace, switch programs, and stabilize the carbon potential. The complicated process is highly efficient.

The working environment is good, and the production pollution is less. The traditional continuous furnace needs to burn the exhaust gas in the furnace with an open flame, which emits carbon dioxide, and requires a large amount of cleaning agent to clean the parts after heat treatment, and the overall operating environment is poor. The vacuum furnace will not have related problems, the whole process is free of oil and oxidation, and the parts do not need to be cleaned.

Equipment requirements

It consists of a front cleaning machine, a pre-oxidation furnace, a main carburizing furnace, a quenching chamber and a tempering furnace. The periphery includes auxiliary equipment such as a vacuum pump system, a helium recovery system and a cooling system.

Process flow

The pulse carburizing method is adopted to realize the carburizing process and meet the requirements of the depth of the carburized layer and the metallographic structure of the product through multiple strong infiltration (passing in the carburizing medium acetylene) + diffusion (passing in the protective gas nitrogen) and a centralized diffusion process. Require. After the parts are carburized, they enter the quenching chamber through the moving chamber, and a large amount of helium gas is instantly introduced to make the gas flow at a high speed to achieve the purpose of cooling and quenching.

The pulse carburizing process parameters are simulated by the simulation software according to the total surface area of the parts, the material of the parts, and the layer depth requirements. The parameters include the carburizing temperature, the number of carburizing pulses, the pulse time and the pulse process gas flow.