Brazing

Introduction

In today’s world, we see different kinds of machines used everywhere. Many of those machines are made out of metals where two different pieces of metals are put together. Both small machines and heavyweight machines are made by the process of brazers and brazing. Brazing is an important process that helps in joining two pieces of metals together. The following paper describes what is brazing and the types of brazing along with other details. 

What is brazing?

The brazing process involves joining two pieces of metal together with the help of an alloy of non-ferrous nature that has been introduced in its liquid state. After applying the liquid nonferrous alloy it is kept aside to allow cooling and solidifying. The alloy that is used to join the two pieces of metal, processes a melting point of 600°c. The alloy is therefore melted at this temperature but the two metal pieces which are being joined have a higher melting point. The metal that is used as a filler spreads due to capillary action. The process of brazing is quite similar to soldering. However, soldering does not give a stronger joint than brazing. The basic difference between the process of brazing and soldering is the usage of a stronger filler material that is also known as a speller. The speller joins at a specific temperature that is lower than the red heat, and thus it nuts below the melting point of the two pieces of metal that are needed to be joined. 

Types of Filler Metal Used in Brazing

Although there are a plethora of alloys that can be used as filler materials, brasses, with twenty percent of tin, are used most commonly. This brass alloy possesses a melting point that ranges from 850°c to 250°c. Silver alloys have a melting point ranging from 600°c to 850°c and they are used as fillers for the process of brazing any metal which is capable of brazing. Silver alloys provide a clean finish and a sturdy joint that is quite ductile. Simulating the process of welding and soldering, the pieces of metals which are being joined by the process of brazing are first cleaned so that they are devoid of any kind of oil or oxides. The clearance between both surfaces is very small. The application of the flux is done and the pieces are applied together with appropriate clearances to fill the metal that is used as a filler. After this process, they are heated till the temperature reaches 600°c. Then using the capillary action the molten metal is free to flow and get into the spaces between the parts which then slowly cool down. The most common material that is used as a flux is borax. The major advantage of joining two pieces of metal by applying the process of brazing is, even if the two metal pieces are not similar, they can join easily. The process of brazing is usually used while joining pipes, tanks, heat exchangers, or different electrical parts. 

Types of brazing

The following is a list of the types of brazing.

• Torch Brazing

In mechanized brazing, torch brazing is one of the most common brazing processes. Torch brazing is used for the production of metals on a small scale or on some special occasions. Torch brazing has three different classifications like manual torch brazing, machine torch brazing, and automatic torch brazing. 

• Furnace Brazing

Furnace brazing is one of the most commonly used brazing processes. This process is widely used among industries that deal with joining metal pieces using the brazing process. Industries prefer this brazing process because it is very flexible and the work can be done even if the laborers are working or not skilled enough. The advantage of using the spacing processes, a large number of small parts can be easily joined using this brazing process.

• Braze Welding

Breast building is a brazing process where a brass or a bronze filler rod is coated with flux so that it can be attached to the steel workpiece. The different equipment which is required for braze welding is the equipment identical to the brazing process. 

• Cast Iron Welding

Cast iron welding is usually performed with the help of a brazing operation in which filler rods are made out of nickel. However, proper welding using cast iron rods is possible as well. The main reason why this process of brazing is used is using electricity with copper so that underground climate pipes can be kept warm during cold climates. 

• Vacuum Brazing

This is an expensive brazing process where the whole process takes place inside a vacuum chamber vessel. If this brazing process is used then the result will be clean, flux-free, strong, and of very high quality. 

• Dip Brazing

This type of racing is suitable when aluminum is used because the air is excluded and therefore there is no formation of oxides. 

Conclusion

Brazing is an important process that assists in constructing something that is made out of metals. The process of brazing must be properly understood by mechanical engineers because they often need to make products based on metals. Thus, students who aspire to become mechanical engineers must have a clear idea of brazing.