What is vacuum high pressure gas quenching?
Vacuum high pressure gas quenching refers to the mold steel, high speed steel, high alloy easy to quench materials, loaded into the vacuum furnace pumping process specified vacuum degree, heated to the critical temperature Ac3 or Ac1 above, insulation for a period of time, and then filled with high pressure inert gas or inert gas N2, process gas charged to the specified pressure (10bar,20bar, 40bar) A heat treatment process of martensite quenching is obtained by driving a heat-resistant fan with a high-power fan to purge the high-temperature hot workpieces at a high speed, and cooling them with a special heat exchanger.
Schematic diagram of quenching temperature range of steel
Advantages of vacuum high pressure gas quenching
1. The workpiece surface quality is good, no oxidation, no carburization, no alloying element dilution;
2. Good quenching uniformity, small deformation of workpiece;
3. Good controllability of cooling speed. The cooling speed can be controlled by changing the aeration pressure and airflow velocity direction, and the fan speed (frequency conversion), so that isothermal quenching can be realized under ideal conditions
4. No pollution and exhaust emissions in the whole process, no secondary cleaning of gas quenching workpiece, high efficiency, energy saving and environmental protection.
The main factors affecting the quenching effect of vacuum high pressure gas quenching equipment
The main factors affecting the cooling rate of the workpiece
The main factors affecting the quenching depth of workpiece
Main factors affecting the uniformity of workpiece quenching hardness (gas flow mode in furnace)
Square thermal field structure
Through the nozzle of the air flow distribution plate, the high speed cold air is injected to the workpiece, and the hot air is discharged through the distribution plate. After heat exchange through the heat exchanger, the air is circulated back along the pipe and blown to the workpiece to achieve isothermal cooling. The process is completed according to the user's setting.
Main factors affecting the uniformity of workpiece quenching hardness (gas flow mode in furnace)
Circular thermal field structure
The nozzle type can arrange multiple nozzles along 360° around the hot chamber, so that the air flow blows to the workpiece in all directions, and achieve uniform cooling, and the system structure is simple, the most widely used
Triple cooling effect
Unique rear air flow technology, triple cooling function, front and rear double heat exchanger configuration, better effect
Application of vacuum high pressure gas quenching furnace
Application of Vacuum High Pressure Gas Quenching furnace (300M steel, 10bar N2 gas quenching)
Hardness test results of 300M steel cylindrical specimens Ф 60 mm round rod core quenched structure
It can be seen from the figure that the hardness of Ф60 round rod reaches the oil quenching effect (generally about 53HRC), and the core is lath martensite structure, good hardenability. However, the Ф80 round rod did not meet the above requirements. This shows that the degree of quenching of the workpiece is affected by the quenching capacity of the equipment
Application of vacuum High Pressure Gas quenching furnace (8Cr4Mo4V steel, 0.2MPa N2 gas quenching)
Test results of 8Cr4Mo4V steel roller bearing D10 XX /01 under gas/oil quenching process
Quenching requirements: hardness 60 ~ 64HRC; Organization level M2 ~ M4; The deformation (cylinder, flatness) should be controlled between 0.20mm.
When hardness and structure are up to standard, the unqualified rates of roundness and flatness of gas-quenched workpieces are 20% and 10% respectively, while those of oil-quenched workpieces are 70% and 70%. It can be seen that the gas quenching can significantly reduce the deformation of workpieces
Vertical bottom loading true air quenching furnace
Technical characteristics of vertical bottom charging true air quenching furnace:
The furnace body is vertical, single chamber, bottom charging form, especially suitable for long rod workpiece;
The bottom door lifting transmission mechanism adopts ball screw, linear motion, not easy to jam, with protective cover to prevent dust pollution;
The lifting bracket is equipped with an automatic balance correction mechanism to automatically eliminate the accumulated error of the lifting system. Smooth lifting, no vibration;
Variable direction cooling technology, not only longitudinal jet cooling, but also 360° circular cooling.
ACME horizontal vacuum high pressure gas quenching furnace
Technical characteristics of horizontal vacuum high pressure gas quenching furnace
The furnace body is horizontal, single chamber, horizontal charging form, suitable for complex shape of the workpiece;
With modular design, furnace temperature uniformity and cooling uniformity are good;
Depending on the different cooling rate requirements of the parts, a single heat exchanger and a dual-stage or even multi-stage heat exchanger can be selected for cooling structure;
For the actual treatment of parts can choose rear suction air quench circulation system or front suction air quench circulation system;
Unique two-stage heat exchanger, the heat transfer area is doubled compared with conventional.