Tue, 24 Jul 2018 02:38:40 +0000

Application of vacuum carburizing technology

Abstract: dual chamber carburized oil quenching gas cooled vacuum furnace features high efficiency, energy saving, precise temperature control, good temperature uniformity and good process reappearance. For alloy steel, high speed steel, mold, gear. Dual chamber carburizing oil quenching gas cooling vacuum furnace, with two functions of oil quenching and carburizing, the equipment has novel structure, advanced performance, low energy consumption, safety and reliability.

Overview;

With the rapid development of China’s equipment manufacturing industry, the demand for gear is increasing day by day. Gear working load, strong impact force, high safety requirements. In addition to good wear resistance, there are also high contact fatigue strength and flexural fatigue strength. At the same time, it has high impact resistance and overload resistance.

In recent ten years, people have shown great interest in using the vacuum system for carburizing, and the technology of low pressure carburizing has become more and more mature. Compared with gas carburizing, low pressure carburizing and gas carburizing can not only form non-oxide and non-pollutant surfaces, but also combine carburizing and gas quenching to improve the deformation behavior of parts, increase the carburizing temperature, reduce the intermittent processing time, greatly reduce the gas and energy consumption, and prevent carbon black from occurring

Low pressure vacuum carburizing process;

1. Definition of vacuum carburizing; Low pressure vacuum carburizing is an improved gas carburizing process. Carburizing is far below atmospheric pressure, and the typical pressure range is 300-2500pa. The advantage is that the steel surface remains very clean, because without gas interaction, carbon can reach the steel surface faster in a vacuum environment.

2. When carburizing, the hydroxyl gases are introduced into the carburizing chamber, and the activated carbon atoms are dissolved, which freely penetrate into the surface of the steel, while the hydrogen and the remaining hydrocarbon by-products are excluded by the vacuum pump system. At present, the hydroxyl gas with vacuum carburizing is acetylene (C2H2).

3. In low pressure vacuum carburizing, the cracking of hydroxyl gases is an unbalanced reaction, which means that the steel surface can soon reach the carbon saturation level in austenite. The desired carbon distribution and depth of the percolation layer can be obtained by repeating several steps of strong percolation and diffusion.

4. The control of low pressure vacuum carburizing process is “austenite carbon content saturation control method” based on diffusion theory, that is, the whole carburizing process consists of several carburizing procedures, each of which consists of two stages of strong carburizing and diffusion. To determine the number of each sub-carburizing program and each carburizing program, including the strong infiltration period and diffusion period, it is necessary to calculate by computer after establishing a certain mathematical model according to the requirements of material composition, infiltration depth and surface carbon concentration.

Characteristics of low pressure vacuum carburizing;

1. Low pressure vacuum carburizing can greatly reduce production cost and improve equipment utilization rate. This is because the atmosphere of low pressure vacuum carburizing is very simple, only acetylene is needed for strong permeability, nitrogen for diffusion and very low pressure, so the cost of using atmosphere is significantly reduced. In addition, due to the characteristics of low pressure carburizing equipment and technology, high temperature carburizing can be carried out, so raising the carburizing temperature appropriately can greatly shorten the carburizing time.

2. Because the control system of low pressure vacuum carburizing can precisely control the carburizing process, the workpieces treated have good repeatability, small deformation and bright surface, so mechanical processing is not necessary after carburizing.

3. The low-pressure vacuum carburizing technology has greater flexibility, and its equipment can be used as independent equipment, or it can be connected with a production line for cold processing. The equipment itself can be periodic, suitable for small batch, multi – variety production. It can also be continuous, with multiple heating cementing Chambers, gas quenching chamber oil quenching chamber, incoming and outgoing material chamber, vacuum system, automatic workpiece transportation system and other components, suitable for mass production. In addition, it is very simple to stop the furnace, each furnace only needs half an hour to enter the working state.

4. Low pressure vacuum carburizing adopts cold wall vacuum technology, no ignition device, no fire risk, no pollution, cleanliness, safety, simple operation and easy maintenance.

Characteristics of low pressure vacuum carburizing equipment;

1. Users can make a variety of choices for vacuum carburizing equipment according to different requirements; One room, two rooms, three rooms,

2. Optional according to the loading mode of workpiece; Vertical, horizontal,

3. According to the quenching mode of the workpiece, it can be selected; Oil quench, gas quench

4. According to the different functions of the treatment room, the preheating chamber, carburizing chamber and quenching chamber can be selected in the equipment

5. Different sizes of furnaces in different effective heating zones can be selected, corresponding to different furnace loading quantities.

6. The equipment can be installed in the heat treatment workshop or formed a production line with the cold processing equipment.

7. According to the production volume, the equipment can be either periodic vacuum carburizing equipment or production line vacuum carburizing equipment.

8. Low pressure vacuum carburizing equipment has many USES and can flexibly realize various heat treatment processes, such as vacuum carburizing, vacuum carburizing, vacuum carburizing + oil quenching, vacuum carburizing + gas quenching, and all functions of vacuum furnace. It can also be used for heat treatment of various materials and parts in the industrial field. Low pressure vacuum carburizing equipment has many USES, can be a variety of flexible heat treatment process, such as vacuum carburizing and carbonitriding vacuum, vacuum carburizing and quenching + + oil gas quenching, and can have on the various materials and parts for industry use relevant heat treatment, such as 12 cr2ni4a, 12 crni3a contour and gold carburizing steel carburizing and quenching after carburizing, 20 crmnti such as structural steel carburizing and quenching after carburizing, 1 cr13 stainless steel, such as the carburizing and quenching after carburizing, H13, W6Mo5Cr4V2 and other industrial die steel quenching, gear parts, axle sleeve parts, precision bearings, oil pump nozzle machinery parts, precision machinery parts, such as quenching, annealing.