BOC will work with you to produce the most durable metals for today’s demands. We offer a diverse portfolio of heat-treating gases and applications that can improve the quality and appearance of your metals, help you make highly reproducible parts, and give you more control over your process. 

Whether you are treating aircraft and automotive components or producing batch metal parts, we can help you find ways to effectively treat your metals, so you never have to choose between cost and quality.

Annealing is a process that softens the metal, causing changes in its strength and hardness. The process is done by heating and maintaining a suitable temperature, followed by controlled cooling. If done correctly, the process increases the ductility of the metal, eliminating internal stresses and allowing for an increase in the workability of the material after the annealing process is complete.  

The correct furnace atmosphere is key to successful and reproducible annealing. Without a controlled atmosphere, the high temperature of annealing causes oxidation of the metal’s surface, resulting in scale. It can also result in unwanted decarburisation. A controlled atmosphere is essential for annealing stainless steels and most non-ferrous metals.  

Whether you anneal ferrous or non-ferrous metals, BOC can provide you with the gases and atmosphere control systems needed, such as carbon monoxide mixtures, hydrogen, and nitrogen-based systems. The system chosen gives you control over the carbon levels found in your furnaces and enhances your heat treatment cycles, helping to improve the quality of your results.  

If you are looking for high surface quality and a bright finish, we offer a nitrogen-based atmosphere system. This system, combined with an external endogas generator gives you the flexibility to create the correct composition to meet your metal requirements. The benefits include a carbon-neutral atmosphere with no decarburisation, brighter surface results with no deposits, increased safety by having a nitrogen-based safety purge and minimised scrap and rework of materials

To harden steels, they are normally heated to above the upper critical temperature (over 900°C). The metal is then cooled rapidly in a quenching medium, such as oil, water, brine or gas. This process increases the hardness and strength of the steel. Neutral hardening and tempering produce strength and toughness on parts that will be highly stressed.

Case hardening is an ideal heat treatment for parts which require a wear-resistant surface and a tough core, such as gears.

Carburising is a case hardening process in which carbon diffuses into the surface layer of steel parts at temperatures high enough to change the steel grain structure. After quenching, the result is a wear-resistant layer that makes carburising an ideal process in the production of hard-wearing mechanical components, tools and fasteners. Carbonitriding diffuses carbon and nitrogen into steels where through-hardening is required.

Our CARBOFLEX^® nitrogen-endogas solution offers a nitrogen-based atmosphere system in combination with an external endogas generator. CARBOFLEX^® can be used to create furnace atmosphere zones with varying compositions to meet the requirement of specific alloys being treated. This avoids decarburisation, enables high surface quality (bright surface, no carbon deposits), achieves high level of safety by using a minimum volume of flammable gases and a nitrogen-based safety purge function. This reduces costs by minimising total gas consumption, scrap and rework.

Vacuum carburising—also known as low pressure carburising (LPC)—demands an atmosphere that is highly reproducible and highly controllable. BOC’s CARBOTHAN^® nitrogen and methanol technology, combined with a precise atmosphere control system can provide ideal conditions for better control and repeatability.

Our CARBOFLEX^® atmosphere control system is specially designed for advanced atmosphere control during carburising, neutral hardening and annealing in continuous furnaces. It gives you full control over the carbon potential in up to four zones per furnace, also optimising the heat treatment cycle. Furthermore, its functions provide indispensable support for quality assurance purposes.

Gas quenching is an important step in the furnace heat treatment of steel parts. The process consists of cooling the parts down from their critical temperature quickly, in order to strengthen and harden the steels. A variety of mediums can be applied to the quenching process. These include gases such as helium, argon, and nitrogen. The overall choice should be made based on part size, steel composition, and desired results. 

Typically used in vacuum furnace applications, gas quenching can provide a variety of advantages over traditional polymer or oil-based quenching approaches i.e. no residues. Gas quenching also provides better temperature uniformity, improving consistency of properties and reducing the risk of part distortion. Once all the components of our process are in place, BOC can easily integrate the gas supply system that best meets your needs.

Many conventional heat treatment furnaces have purge or inerting requirements. This is done to remove or clear unwanted material from the furnace atmosphere. 

A nitrogen or argon-controlled atmosphere is most commonly used for this application. As nitrogen or argon is introduced into a furnace, the risk for oxidation of the component parts being heat-treated is reduced. The inerting process is also done as a safety measure since the gases used purge flammables, oxygen, and water from the furnace. The amount of gas flow required for your furnace varies and is based upon your furnace volume.  

BOC offers nitrogen, argon and other gases that can provide an inert atmosphere that prevents reaction between air and components.

Sintering is a process that uses compressed metal or ceramic powders to form various shapes. These structural parts are usually complex. Almost all metals can be sintered, but pure metals with little to no surface contamination result in a better product. The process of sintering at atmospheric pressure requires a protective gas such as hydrogen, nitrogen, or carbon monoxide. Using nitrogen and hydrogen-based atmospheres results in a more consistent performance for your sintering operation. Our atmospheres that use hydrogen or carbon monoxide are considered reducing agents. They work together and protect the sintered parts from oxidation and decarburisation. 

Benefits of sintering:  

• Reproducible size and hardness 
• Brighter and cleaner parts 
• Decreased soot formation and oxidation 
• Fewer process interruptions 
• Decreased idle furnace time 
• Faster start-ups

Brazing is a joining process that heats filler metal to a fluid temperature and evenly distributes it between two close-fitting parts. Brazing allows you to join the same or different metals without melting the base metal. Brazing forms an adhesive bond similar to soldering. The molten filler metal adheres to the base metal to form a strong, sealed joint. Plumbers and gas fitters have used this process manually for over a century.  

In manufacturing, brazing of large batches is normally carried out in a furnace. Furnace brazing requires the right atmosphere to facilitate a strong brazed joint and better surface quality. This process allows for controlled heat levels and increased production. While furnace brazing has its benefits, the high heat can cause oxidation if the atmosphere contains oxygen. These oxides hinder the brazing process. 

We can provide a reducing atmosphere (depending on alloys involved) that consists of hydrogen and nitrogen to minimise oxide formation and reduce existing oxide, ultimately resulting in higher quality joints. Our technologies enable customers to control and optimise furnace conditions, and as a result of the improved atmosphere composition, reduce total costs. 

BOC can provide information on the best gases to use for your brazing process. To install the complete system at your site, there is a team of experienced professionals ready to help meet your needs. 

After your installation is complete, our monitoring system can check the atmosphere in your continuous and batch furnaces and control the volume of gas introduced into the furnace. The advanced atmosphere control system helps generate higher quality parts and increases the efficiency of your heat treatment operation.