Aluminum Brazing, Types, Advantages and Disadvantages

Aluminum brazing is the process of welding or joining two metal parts by filling or repairing them under a controlled temperature. These metals can be aluminum and called base metal. The braze alloy or filler metal is used with a lower melting point to fill the holes, and joints.

One main point during this process is to get that filler metal that has a lower melting point than the base metal. Otherwise, while heating base metal itself will melt, also change the metal shape.

Aluminum Brazing Process Guidelines: –

Here in this process Gas generated heat is used to melt the filler metal for filling or repairing the cracks. In some positions aluminum brazing excellent results even better than original.

There are no special requirements for aluminum brazing like having any professional training. You can easily braze aluminum with some common welding knowledge. Some basic should be followed to get better results.

1. If the base aluminum metal is flat, the brazing process will give strong joint bonding. Otherwise, in case
2. Thinner gauges of base metal need some extra care regarding temperature control, because uncontrolled temp may burn the base metal.
3. During brazing aluminum base metal surface should be clean for stronger joints and repairs. At room temperature, aluminum metal surface gets oxide cover via an oxidation process.
4. Aluminum brazing process requires lesser equipment like it do not need argon shielding gas, gloves, and wire spools.
5. Brazing aluminum is quite a simple process but brazing other metals like titanium and copper need some innovative process moves.
6. Silicon or Zinc in the braze filler enables it to melt at a lower temperature, and during the process these extra metals evaporate and the remaining filler metal like aluminum starts filling the cracks.

Advantages Brazing Process: –

1. Easy, and less risky form of the welding process.
2. Low-Cost welding process due to less equipment required.
3. It requires less power than the TIG welding process.
4. Post-processing heat treatment is not required.
5. Two different types of metals can be joined.

Disadvantages Brazing Process: –

1. As brazing does not require any specialized gadget so the joints are not stronger as through welding.
2. This process may release toxic components.

Aluminum Brazing Rod & Flux: –

This brazing kit includes a brazing rod and a flux. Here brazing rods are used to repair or fill the cracks. The basic element of these rods is aluminum. But here zinc or silicon can also be used to lower the rod melting point than the base metal. There are various quality aluminum brazing rods available in the market.

Another important thing that is used in aluminum brazing process in flux. This is a powder type solid substance that includes chloride and fluoride salts. The basic purpose of this flux is to minimize oxidation, and hydrogen penetration. It gives clean processing results.

Brazing Filler Metals: –

There are various filler metals that can be used according to the type of base metal to be brazed. Sometimes, the filler metal is comprised of more than one element. This combination is to lower the filler metal melting point than the base metal.

According to the base metal melting point elements like copper, zinc, silicon, and magnesium is mixed in the aluminum alloys. Brazing filler metals are available in the market with different comprising components.

Types of Brazing Processes: –

Brazing is an easy form of joining two or parts of the same or different metals. In this process, a solidify liquid alloy is used. Overall, there are various forms of brazing which we have explained below.

1. Torch Brazing: –

This is the first type of brazing which is a customized operation for producing a small number of joints. Torch brazing is a widely used method that consumes resources as per the requirement. So, it is less costly them other methods. Further, this method is categorized into three types i.e. manual torch brazing, machine torch brazing, and automatic torch brazing.

2. Furnace Brazing: –

Opposite to the first type this method is used for bulk joint productions. This method is used for large manufacturing companies like the automotive industry. Most of the time this method is automatic due to which unskilled labour can be used during this process. This is considered an ideal method for mass production.

3. Silver Brazing: –

Normally in the aluminum brazing process, the rod filler is made of aluminum with a mix of zinc or silicon. This mix is used to lower the temperature than the base metal. But in silver brazing, the filler metal is comprised of silver, copper, and zinc.

4. Braze Welding: –

This is a different process than normal brazing as it requires more heat. Bronze filler is used to weld the steel pieces. Further, all equipment requirement of braze welding is same as brazing, that is why it is called braze welding. You can also apply this process to dissimilar metals.

5. Vacuum Brazing: –

This is an expensive technique if brazing in which the function is performed in a vacuum chamber. The temperature inside the chamber is controlled during the whole process. Though this method is expensive, it gives extremely clean and quality results.

The process is normally performed in a customized environment where mass production is required. Further, this can only be performed with skilled labour.

6. Dip Brazing: –

This form of brazing excludes air from the operational area and mostly used for aluminium brazing. When this technique is used during the aluminum brazing it eliminates oxygen from that area. Further due to this prevents the formation of oxides and keeps the aluminum clean. It provides more clean quality results.

7. Cast Iron Welding: –

Cast Iron welding is also a form of brazing operation in which the “Nickle” metal rod is used for joining cast iron base metal. The welding option is always there and small copper wire can be fused to weld the cast iron joints. [More info]

Brazing Vs Welding: –

You can weld most of the metals with normal welding machines. But when it comes to aluminum welding only AC TIG welders can only perform this job. These TIG welders are expensive and require professional training as well. Here you can replace aluminum welding with the brazing process. As aluminum brazing process does not need any TIG welding machine so which makes this process less expensive than TIG welding.

The temperature in the brazing process is lower than welding as the base metal is not fused in brazing. In brazing, a bond is created between base metal parts via filler metal. Brazing is quite an easy process than welding, so unskilled labour can also perform this with simple instructions.

Normally brazing function is performed in automobile air conditioning systems, turbine blades etc. A properly made joint is as strong as a strong welding joint.