Retort Furnaces Argon-Hydrogen

What is a Retort Furnace?

Retort furnaces have a sealed vessel that is placed over or around the product and separates the product and process space from the system insulation and heat source. Retort furnaces allow accurate and efficient control of the work space Argon or Hydrogen atmosphere and provide low atmosphere usage due to the closed nature of the system. Max temperatures of 1300°C/2400°F; dew point of -60°F or better.
Retorts can be fixed mounted in Front Loading Box Furnaces with gasketed doors, Pit Furnaces with a flange at the top, or moveable in Bell Furnaces that are lowered over a fixed base, or Bells permanently mounted inside the heating chamber of a Bottom Loading Furnace or shaker hearth furnaces.
In the aerospace industry, large format retorts allow the fabrication of macro-scale carbon composite assemblies and the processing of large scale titanium aircraft parts. Very large parts can also be processed in a cold wall furnace to avoid the costly retort.

Choose the Right Atmosphere (gas) for Your Process
Most retort furnace applications use a nitrogen, argon, or hydrogen atmosphere. Selecting the correct atmosphere depends on the material being processed, the desired surface finish, operating temperature, and the metallurgical results you want to achieve. Each atmosphere offers unique advantages depending on your application.

Do I need an Argon Retort, Hydrogen Retort or a Nitrogen Retort?
Use the comparison chart below to help determine whether a nitrogen, argon, or hydrogen atmosphere is best suited for your material and heat treating process. While all three provide controlled atmosphere processing, each offers different benefits depending on your material, process requirements, and desired surface finish.



* Carbon steel is not ideal for hydrogen because it’s highly susceptible to hydrogen embrittlement. This is where hydrogen atoms diffuse into the steel,  weakening it and causing cracks, especially under stress or high pressure.

** Titanium is risky to heat treat in hydrogen because it absorbs hydrogen at high temperatures causing hydrogen embrittlement or forming titanium hydride, all of which weakens the metal and can cause cracking. It’s only used in hydrogen under very strict conditions—argon is the safer choice for most applications.

*** Aluminum is risky with hydrogen because it can react with moisture (or hydroxide) to generate hydrogen gas, posing explosion risks in certain environments. Also, at high temps, it lacks strength and can’t handle hydrogen's reducing conditions well.

Which Type of Retort Furnace Do You Need?
 

ARGON RETORT FURNACES	HYDROGEN RETORT FURNACES	NITROGEN RETORT FURNACES
Inert Atmosphere Processing Argon retort furnaces are used when parts must be protected from oxidation without chemically reacting with the atmosphere. Best suited for: Reactive metals such as titanium Aerospace titanium/aluminum components Carbon steel Sensitive alloys requiring ultra-clean processing   Learn More About Argon Retort Furnaces	Reducing Atmosphere Processing Hydrogen retort furnaces are used when surface oxides must be removed or when bright, oxide-free finishes are required. Best suited for: Bright annealing of stainless steel Powder metallurgy sintering Brazing and heat treating processes   Learn More About Hydrogen Retort Furnaces	Economical Protective Atmosphere Processing Nitrogen retort furnaces provide an oxygen-free atmosphere for many common heat-treating applications at a lower operating cost than argon. They are ideal when oxidation protection is required, but a completely inert atmosphere is not. Best suited for: Carbon steels Tool steels Many stainless-steel grades Stress relieving Tempering General industrial heat treating Cost-sensitive production environments Learn More About Nitrogen Retort Furnaces

Need More Help Selecting the Right Retort Furnace?
Keith Company engineers custom retort furnaces for both inert and reducing atmosphere applications. Our team can help determine the best atmosphere based on your materials, process requirements, and production goals.
Contact us to discuss your retort furnace application.