Precise Control and Advantages of Vacuum Gas Quenching

Why Use Vacuum Heat Treatment?
When increasing the hardness of steel, it must undergo a metallurgical process. This process occurs when the steel is heated to undergo a phase transformation to the austenite range, followed by rapid cooling, which completes the phase transformation from austenite to martensite. During vacuum quenching, a significant temperature gradient is generated across the workpiece geometry. If the vacuum quenching is uneven, this can lead to residual thermal stresses and uneven microstructural transformation. This can also cause significant deformation relative to the preheated geometry.

Vacuum Gas Quenching Principles
Vacuum gas quenching is performed in a vacuum furnace. In most cases, the quenching medium used in vacuum gas quenching furnaces is nitrogen, although hydrogen, helium, and argon can also be used in special cases. Compared to liquid quenching, vacuum gas quenching is much less severe, and due to the dynamic characteristics of vacuum gas quenching, it causes less geometric distortion in the quenched workpiece.

Advantages of Vacuum Gas Quenching
Vacuum gas quenching is becoming increasingly common in industrial applications and offers many benefits. These include:
High-quality (clean and bright) parts after vacuum heat treatment
Excellent process repeatability
Environmentally friendly
No IGO
Minimized quenching distortion
Fully automated heat treatment process
Easy process setup
Full SCADA system
Vacuum furnace multi-process flexibility
Compact design

Vacuum Gas Quenching Furnace Application Design
Vacuum furnaces come in many different designs, including single-chamber (vertical and horizontal), multi-chamber (batch and semi-continuous), and fully continuous (single-piece flow). Each design serves its own purpose. The most commonly used vacuum furnace design is the single-chamber vacuum gas quenching furnace, in which the quenching gas enters the hot chamber through nozzles located around the perimeter and is directed toward the center, enveloping the workpiece.
The use of horizontal vacuum furnaces significantly improves the quenching process by reducing distortion. Gas quenching is a one-stage process, resulting in a more uniform process for each workpiece. Furthermore, by varying the gas pressure (density) and speed (fan speed), the quenching rate can be freely adjusted, making the quenching process controllable. Vacuum gas quenching systems using nitrogen or helium, operating at 25 bar absolute pressure, offer the same performance as oil quenching. As an added benefit, gas quenching eliminates the need for cleaning, making it a more environmentally friendly process. They are flexible and can be turned on and off at any time, requiring only approximately one hour to set up for production. Furthermore, they require no atmosphere stabilization, and process parameters can be changed almost instantly.

Vacuum Gas Quenching Furnace

Learn More:

Vacuum furnaces are widely used in various fields

Processing principle of vacuum heat treatment technology

Optimization of vacuum brazing quality of water cooling plate