Frequently Asked Questions : Parfuse Corporation Aluminum Dip Brazing Westbury Long Island New York

The Following are Typical Aluminum Dip Brazing Questions

What Is Aluminum Dip Brazing?

One of the most efficient methods of joining aluminum parts is Aluminum Dip Brazing. This is a process of joining two (parent) pieces of metal simultaneously with a third; molten filler metal. By uniformly heating the joint area above the melting point of the molten filler metal but below the melting point of the parent metals; the molten filler metal flows into the gap between the other parent pieces by means of capillary action. As the assembly cools, a remarkably strong metallurgical bond is achieved. The brazed joints are often stronger than the two (parent) metals being joined together. Because the parent metals being joined are not melted, they are not distorted or out of shape and hold on to their original metallurgical characteristics. Dip Brazing may be the most versatile method of metal joining available. Configurations of the greatest complexity are thus perfectly joined in one Dip Brazing operation, regardless of the number of joints involved. Brazed joints: are unaltered by typical changes in temperature, minimize distortion and resist vibration/shock. Dip Brazed joints have an exceptionally clean, refined appearance; leaving Aluminum Dip Brazing as often the ideal metal joining method for various industries. There are many cost savings advantages by using this brazing process.

Does Aluminum Dip Brazing Seal Assemblies?

Aluminum Dip Brazing achieves strong leak-tight joints regardless of the number of joints and the thickness of the base materials. Through capillary action, the process seals the joint with continuous leak-tight properties. This property is required in EMI/RFI applications. The majority of instrument and part assemblies require leak-tight joints which Aluminum Dip Brazing provides. Visual inspections confirm if the assembly is sealed properly. In addition, we can recommend additional testing procedures for assurance of leak-tight assemblies.

When Does Aluminum Dip Brazing Work Best?

With so many options for joining metal, when does this process of brazing work best? When considering which metal joining method to select for a specific assembly, some factors need to be considered: strength, the physical characteristics of the components, permanence, the nature of the joint and the production level required.

Brazing as Compared to Other Metal Joining Methods

The following Table A rates the various metal joining methods; good, better and best. Brazing rates the best in strength, control and flexibility and is better than other methods in economics and energy used.

Please see Table A for properties:

Table A	Economical	Strength	Energy Used	Control	Flexibility
Mechanical Bonding	Best	Good	Best	Good	Good
Adhesive Bonding	Better	Good	Better	Good	Good
Soldering	Better	Better	Better	Better	Better
Welding	Good	Good	Good	Best	Better
BRAZING	BETTER	BEST	BETTER	BEST	BEST

For many application, brazing is the best overall solution.

The Dip Braze Advantages

The Economical/Cost Advantages of Using Aluminum Dip Brazing

There are numerous cost advantages in using the process. Comparatively, Dip Brazing yields the lowest cost given its best characteristics in strength, control & flexibility. Material costs are lower in dip brazing than that of assemblies using expensive castings and time consuming machining operations. Dip Brazing aides in facilitating the fabrication from lower cost materials such as Aluminum. Costly special tooling is minimized; instead simple and multi-purpose fixturing is utilized. A Dip Brazed assembly’s finish is uniform, clean and smooth. The even continuous joint left by the process requires little if any mechanical finishing. Time savings is another cost advantage. Regardless of the number of joints involved in an assembly, joining is performed in one dip braze operation, minimizing time and costs.

The Strength Advantages of Aluminum Dip Brazing

In the Dip Braze process, the filler metal melts and flows into all joints through a capillary action. The beauty of this process is that even a simple joint will have equal or superior strength than the base metal. One of the characteristics of the Aluminum Dip Brazed joint is such that even basic joints will be equal to or stronger than the parent metal. Temper can be restored by an aging process to T4 or with an extended heat treatment operation (artificial age) to achieve a T6 temper. When the filler metal flows onto the base metal, the process of wetting takes place. The filler metal melts and responds with the base metal forming a thin layer called the joint interface. This layer cools to form an entirely different metal; essentially an alloy of the parent and filler metals. Consequently, the brazed joint develops a “sandwich effect” of diverse layers, each metallurgically connected to the next.

Elimination of Corrosion in Aluminum Dip Brazed Assemblies

To assure that all flux is removed from the assembly, excessive cleaning processes, boiling and silver nitrate testing are performed. These precautionary steps are taken by Parfuse Corporation to eliminate any flux residue or corrosion in the assembly. With these precautionary steps taken, Parfuse Corporation takes the worry of corrosion out of aluminum Dip Brazed assemblies. The base metal of the assembly holds the same corrosion resistance factors as the Dip Brazed joints.

Minimized Distortion in Aluminum Dip Brazed Assemblies

Through Aluminum Dip Brazing, the assemblies are uniformly heated to the specific brazing temperatures and allowed to cool at an even rate, thus eliminating distortion and permitting the joining of metals of diverse thicknesses with a positive bond. The application of the Dip Brazing method of joining is limited only by the imagination of the design engineer. The most complex shapes and sizes are brazed with the distortion factor at a minimum. In the Salt Bath, the bath medium contacts the assemblies evenly, heating it uniformly by conduction to minimize distortion. Brazing is quick; salt bath brazing proceeds four to five times quicker than atmosphere furnace brazing, resulting in less thermal distortion of the brazement (at half the cost of furnace brazing). Brazing out performs welding also in the rate of distortion due to its uniform heat application. Other methods of joining such as heliarc, spot and torch welding cause extreme thermal distortion which can not be tolerated in today’s design of precision assemblies.

Final Appearance of Aluminum Dip Brazing Assemblies

Aluminum dip brazed joints form uniform and require little if any mechanical finishing. The process does not leave any unattractive slag at the braze joints. All dip brazed assemblies are chemically cleaned following the braze process. The assemblies are shiny and clean, thus reducing unnecessary finishing costs and time. Glass bead also can create a very uniform finish which is an option at Parfuse Corporation.

Other Advantages of Aluminum Dip Brazed Assemblies

In Aluminum Dip Brazing, the filler metal forms a fillet which resists fatigue. Unlike welding, dip brazing evenly distributes any stresses equally throughout the larger stress area. Dip Brazing is an outstanding method for constantly producing high quality brazed joints in complex assemblies such as waveguides and heat exchangers.