Gear vacuum carbonitriding

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Gas carbonitriding is a traditional heat treatment technique that was extensively studied in the 1960s and widely used in the 1970s. Due to the infiltration of nitrogen, the critical point (Ai, As) of the steel is moved down by this technology, which can appropriately reduce the quenching temperature and provide the possibility to further reduce the quenching deformation. The infiltration of nitrogen also increases the hardenability, so in addition to alloy steel, carbon steel can also be subjected to carbonitriding and oil quenching treatment to improve hardness and surface wear resistance. These two characteristics are also the reasons why the technology is widely used. The infiltration agents used in this technology are: ① ammonia ten kerosene, ② endothermic atmosphere ten rich gas + ammonia ③ nitrogen-based atmosphere ten methanol carpropane + ammonia and so on.

Since the end of the 20th century and the beginning of the 21st century, a pre-vacuum carbonitriding technology has emerged. In the vacuum furnace, the workpiece is heated to the carburizing temperature, and carburizing gas is introduced for carburizing and diffusion; then the temperature is lowered, and nitriding gas is introduced into the vacuum furnace for nitriding. Due to the use of vacuum exhaust and sealing technology, not only the process is shortened, the efficiency is improved, and the amount of penetration agent used is slightly reduced.

Application object

Vacuum carbonitriding can be used for low carbon alloy steel (including alloy structural steel, alloy carburized steel), as well as widely used carbon steel and powder metallurgy steel. For parts with large load, it is recommended to use medium carbon steel, Cr steel, NiCr steel, Ni-CrMo steel, etc. The application objects are parts that require wear resistance and fatigue resistance, such as various gears, shafts, washers (sheets), shafts Bushing (sleeve) ring gear (disc), oil pump nozzle, roller, bearing cap, sprocket (strip), clutch, gate valve, pin, screw (mother, rod), etc.

Gear carbonitriding

The precision gear made of 20CMo steel, its technical requirements are that the depth of the hardened layer is 0.15-0.30mm, the hardness is (550±50) HV0.5, the deformation of the inner hole is ≤0.01mm, and the bell mouth cannot be formed.

Vacuum carbonitriding process.

The treatment temperature is 850°C, the infiltrating agent is hydrocarbon gas (such as acetylene) and ammonia gas, and the pressure is 100-3000Pa. After 120min of co-infiltration of 16MnCE5 steel using this process, the layer depth is 0.45mm, and the hardness is 745HV0.5. Carbon steel The hardenability is poor, the transfer time from the hot zone to the cold room oil tank in the vacuum furnace is long (≥15s), and the oil quenching after vacuum heating cannot be realized. After vacuum carbonitriding, the hardenability increases due to the infiltration of nitrogen. After vacuum heating, oil quenching can be used to improve hardness and wear resistance, thereby prolonging life and saving resources.

Cooling after vacuum carbonitriding can be air-cooled (gas-quenched steel) and oil-cooled (oil-quenched steel). Double-chamber vacuum oil quenching furnace can be used for oil cooling, and the surface is white and bright after oil quenching.

Compared with gas carbonitriding, vacuum carbonitriding is completely free of oxygen intervention, and the infiltrated layer has no grain boundary oxide layer. Applicable to ordinary carbon steel, alloy steel, powder metallurgy parts. The heat treatment deformation is smaller than that of carburizing, and the precision is high. It is of great significance to improve the service life and save resources of basic parts and components in the machinery industry. The new technology of vacuum carbonitriding requires less infiltrating agent gas, and the emission of waste gas is also greatly reduced, which not only saves raw material gas, but also is clean and environmentally friendly, and has been widely used.

Equipment selection: The RVN series vacuum nitriding furnace produced by SIMUWU is a high-quality product for the vacuum heat treatment process of tooling and molds. Good temperature control accuracy and temperature control uniformity ensure the effective progress of the vacuum nitriding process. SIMUWU specializes in the manufacture of vacuum furnaces, has more than ten years of relevant experience, and has a good reputation in the field of vacuum furnace manufacturing. The product line includes vacuum air quenching furnace, vacuum oil quenching furnace, vacuum brazing furnace, etc., which are widely sold in developed and developing countries.