Low pressure Vacuum carburizing and carbonitriding

Midwest Thermal-Vac uses the patented Infracarb process from ECM, which allows low pressure Vacuum Carburizing, Carbonitriding and other case hardening applications to be done under vacuum. By taking advantage of the newest technology available today, we are able to effectively provide our customers the opportunity to utilize the latest streamlined manufacturing process improvements within our industry. This has been shown to yield increased quality in the heat treatment process and a decrease in overall production costs.

Vacuum Carburizing process features:

No intercrystalline oxidizing.
Reduces distortion and overall size change
Superior Part cleanliness
Reduced heat treatment time
Perfectly controlled and reproducible Carburizing depths and narrow tolerances.
Ability to provide a choice of the surface carbon content.
Improved fatigue resistance.
Gas or oil quenching (high pressure gas quench up to 20 bar in specialized cold cell).
Processing temperatures range up to 1250C (2280F).
With a 1000x610x600mm, 500kg capacity, MTV can handle large or small parts.
The heat treatment cycle can be computer simulated and can guarantee the exact requested carbon profile.

Low pressure vacuum carburizing has expanded to encompass the latest demands of the aerospace, automotive and industrial markets, particularly in the areas of new material development. Establishing and controlling critical process parameters are essential. Extensive development work has been done at Midwest Thermal-Vac (MTV) to establish achievable case depths with the required temperature uniformity, to create surface carbon control techniques thus avoiding both carbide networks and necklace formation. Understand thermal characteristics during both heating and cooling when working with parts sensitive to distortion is critical in achieving the desired characteristics.

Vacuum Carbonitriding
MTV uses a carbonitriding process under vacuum which reveals the full potential of this technology in terms of fatigue strength improvements. Compared to traditional carbonitriding and oil quenching, the same tests performed on parts using low-pressure carbonitriding followed by gas quenching show great improvement to tooth root fatigue and overall greater fatigue strengths.

Why Vacuum Carburizing Is in Demand. Only low pressure vacuum carburizing allows the end user to “dial in” settings for case depth, carbon profiles, surface/core hardness and case/core microstructure. With Low presuure carburizing it makes it very easy to predict distortion results which can then be used to achieve required properties at the lowest unit cost. Conventional materials such as 8620, 8822, 9310, and parts that are traditionally atmosphere carburized can greatly benefit from these techniques. Documented savings in post-machining operations and material stock allowances make the use of vacuum carburizing not only practical, but very financially attractive.

Application Examples:
Whether the need is to deliver greater horsepower in smaller transmission packages, survive harsh environments, stand up to the rigors of modern warfare or any one of a number of performance demands, customers are looking to the new generation of advanced materials for the solution. Some typical applications include:
Aerospace Sector — The aerospace industry includes rotorcraft, aircraft, rocketry, space vehicles and shuttles, landers and probes. All are looking to the next generation of materials in the design of such items as propulsion systems, landing systems, control and actuator systems, stabilizers, exhaust nozzles, wing sweep actuators, and the like. Many aerospace clients are working with us and their steel suppliers to optimize their designs, manufacturing methods, and heat treatment processes. One such application is in the commercial airline industry where advanced materials are used in actuator systems .

Automotive Sector — Both passenger car/truck manufacturers and racing teams rely heavily on vacuum carburized components for their engine fuel system, powertrain/transmission, braking, and steering components. Most of the major automotive manufacturers are working to improve performance by vacuum heat treatment. One such application is transmission components, such as those used by the racing industry. Phenomenal race results (Latest NASCAR Results) have been achieved using vacuum carburized components due to increased rear wheel horsepower with equivalent or reduced rotating mass.

Industrial Sector — Industrial applications include heavy duty military components such as transmission gears, hydraulic cams, valves, seats and bushings, as well as tools, tool holders, punches, linear motion machinery, and many others. These components are typically made from more conventional materials.

The Future of vacuum carburizing. Aerospace and automotive specifications need to be reviewed in light of rapid developments underway with these new materials. Serious consideration must be given to the use of elevated temperatures above 1900ºF (1040ºC) for carburizing and direct quenching, to minimize cycle times and reduce carbon absorption without adversely affecting microstructure. Preoxidation treatments have been found to be unnecessary, and rules for the use of high gas pressure quenching need to be better established and realized throughout the industrial sectors. Once this is accomplished, vacuum carburizing technology offers almost limitless possibilities.

For more information and full articles about Vacuum Carburizing please check out our Resources page.