Hydrogen Brazing

Hydrogen Brazing with Controlled Atmosphere Furnaces:

Contributions and Advantages for the Industry

What is Brazing?

Brazing is an effective method for joining two metals through a third filler metal. In this
process, the base metals are brought together, and filler material is placed at the joint. The
filler metal melts at a temperature lower than that of the base metals and fills the gaps.
Depending on the requirements, this alloy, which can be used in solid or liquid form, creates a
strong bond and ensures a leak-proof seal.

What is Hydrogen as a Protective Gas Atmosphere in Brazing and What Are Its Advantages?

Hydrogen as a protective gas atmosphere in brazing is a reliable and cost-effective method for
precision metal connections. High-purity hydrogen reduces oxides on metal surfaces and
ensures effective spreading of the filler material across the connection surfaces, enhancing
the strength of the joint.
This process, conducted in a hydrogen atmosphere, improves the fluidity of the brazing alloy,
resulting in stronger and more durable joints. This method is commonly used for materials
such as stainless steel, brass, copper, and copper-plated (bundy) materials, particularly
providing excellent performance in precision connections.

Belt Conveyor Controlled Atmosphere Brazing Furnaces

Belt conveyor-controlled atmosphere brazing furnaces are equipped with a moving belt
system that transports materials throughout the process. The major advantage of this system
is the ease with which the entire process can be controlled. Additionally, the final products
have very low residual stress values.
The belt speed can be adjusted according to the size, material type, and thickness of the parts
to be joined. High-temperature brazing provides high strength at the joint areas. This method
offers benefits, especially in sealing components, including homogeneous filler material
distribution and obtaining shiny surfaces.

Brazing Furnace Structures

Brazing furnaces ensure continuity in mass production while providing precise temperature
and atmosphere control throughout the process, guaranteeing quality. These furnaces are
commonly used in sectors such as household appliances and automotive, where tight
tolerances are required.
The structure of the furnace varies depending on the type of part to be brazed. Belt conveyor
furnaces can generally be classified into two main types: flat and inclined.

The furnace consists of six main sections:

• Inclined Brazing Furnace (Ramp Type/Arched)
  These furnaces are preferred for brazing and bright annealing processes of stainless
  steel, steel, copper, and copper-plated steel (bundy) pipes. The inclined design
  minimizes the consumption of hydrogen gas in the system.
• Flat Type Belt Conveyor Controlled Atmosphere Brazing Furnace
  Unlike ramp furnaces, the Endogas atmosphere is created inside the furnace.
  Additionally, the flat design minimizes temperature fluctuations during the process and
  ensures the uniform distribution of the filler metal.
  

Furnace Structure and Safety

The furnace consists of six main sections:

• Furnace loading and unloading areas
• Furnace entry and exit exhausts
• Furnace zone
• Cooling zone
• Gas panel
• Control system

Materials are loaded into the furnace from the loading zone and unloaded from the unloading
zone after processing. The entry and exit exhausts ensure that waste gases are vented from
the furnace. Flame curtains in these areas prevent oxygen from entering from the outside and
stop hydrogen gas from coming into contact with the external environment.
During brazing, electric heating is applied at high temperatures in the furnace zone. The
cooling zone is equipped with double-walled water jackets made of stainless steel, which
provide ease of handling and maintenance. The furnace’s protective atmosphere is
maintained with hydrogen gas. To ensure safety, nitrogen lines, regulators, flow meters, and
solenoid valves are also included.
Endogas is supplied to the furnace via a gas generator. Depending on the furnace size, the
number of controlled atmosphere zones may vary. For example, a furnace with a 1800 mm
useful heating length can perform heating in three zones. Precise sensors and thermocouples
are used for accurate temperature measurement in continuous processes.

Industrial Applications

Brazing is a reliable joining method preferred in a wide range of industrial applications.
Common applications include:

• Condensers
• Compressors
• Coolers
• Mining
• Automotive applications
• Motor circulation tubes
• Grouping of bent pipes

In these industries, brazing improves quality by providing superior durability, high sealing
capability, and reliable connections.

Advantages of Hydrogen as a protective gas atmosphere in brazing and Controlled
Atmosphere Furnaces

Hydrogen as a protective gas atmosphere in brazing offers several technical and economic
benefits:

• Reduces oxides on the base material surface, resulting in stronger joints,
• Provides a clean and homogeneous joining surface,
• Offers a wide range of options for base materials and brazing alloys,
• Improves ductility and elasticity,
• Suitable for joining different materials,
• Enables easy and effective joining even in porous parts,
• Prevents surface tension and allows for low production tolerances,
• Avoids issues such as warping, overheating, or melting of the base metal,
• Provides economic solutions with low unit costs.

Brazing Process and Surface Cleaning

In brazing, the filler material must spread homogeneously across the surface of the joined
parts. The filler metal interacts with the base metal surface to form a strong alloy. However,
issues such as the formation of lumps due to the inability of lead to form an alloy with iron can
cause the joint to fail.
Surface cleaning plays a critical role in the successful completion of the brazing process. Oxide
layers, dirt, or oil residues on metal surfaces can hinder the effective spreading of the filler
material and weaken the joint. Therefore, preparing the surface through chemical or
mechanical methods is a vital step for both process safety and joint quality.

Superior Connection Solutions in Industry with Brazing

Brazing is an effective method for joining precision parts with high strength and durability. This
process minimizes the stress on the material surface, eliminating the need for additional
stress-relief processes. Belt conveyor-controlled atmosphere brazing furnaces, especially used
in high-volume production, stand out in terms of stable quality and production efficiency.
At Epta, we carry out brazing processes in state-of-the-art controlled atmosphere furnaces,
meeting high-quality standards. Through precise control during production stages, we achieve
reliable and long-lasting connections for critical parts like sealing elements. We offer
customized solutions to our customers and support your economic production goals. Contact
us for more information!