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October 26, 2020

The duo of these factors affects welding processes the most. These two factors are the expansion and contraction of metal. This blog discusses these two factors and the impact they have on the welding procedures applied to metal.

What Does Expansion And Contraction Do To Metal?

Metals expand when heated and contract as they cool down. When the metal expands, its size, structure, and composition other characteristics change too. Expanded metal is not the same as when it was cold. Another change that it brings is in the strength of the metal. As you heat the metal, it weakens. This is why you can mold, weld, and transform red hot metal into other shapes.

On the other hand, as the metal cools down, it starts getting back its strength. It is complicated and even impossible to then change the shape of the metal once its temperature cools. Once the metal has cooled it is in its optimum strength.

How Is Expansion And Contraction Related To Welding Quality?

These two factors are closely and directly related to the quality and finishing of the welding procedure. When welding experts weld any metal, it undergoes heating and cooling. This variation of temperature changes the characteristics of the metal. This is why it is necessary to control these two factors to ensure the quality of welding procedures.

How Heating And Cooling Affect Expansion And Contraction

If the aviation welding technicians use heat improperly, the metal will expand irregularly, resulting in an uneven welding job that causes the surface of the metal to be inconsistent.

To avoid this unevenness, welding experts need to apply the heat evenly on the metal’s surface. Using heat evenly will result in gradual and smooth cooling, which will result in the perfect shape of the metal that the experts desire to achieve at the welding job.

How Does Uneven Heating And Cooling Affect The Metal?

Have you ever heard of the terms buckling and warping of metal? If yes, you know now that these are byproducts of uneven heating and cooling. You understand buckling as the sideways shift of metal due to uneven heating or cooling. It’s an abnormal and unintended bend in the metal. Warping also refers to a bend or a twist in the shape of metal.

Warping Or Buckling Doesn’t Only Look Bad

When you look at the aircraft exhaust system’s pipes or any other metal component that has suffered warping or buckling, it doesn’t look good. The alarming thing is that it’s not only about bad looks, but a lot more than that. A metal that has undergone warping and buckling is prone to breaking and cracking.

You can say that buckling and warping are the initial stages of cracking and breaking of metal. It is not about the cosmetic aspects but the functionality of the metal components of an aircraft.

The point where the metal twists or bends too much is from where it will start to crack. The thickness and strength of the metal determine when it will break or crack.

How To Control Expansion And Contraction Of Metal

Don’t worry too much, as this problem is avoidable. There is more than one method to control the uneven expansion and contraction of metal during and after a welding job. One preventive measure to take is to use the pre-heating technique before welding. Preheating refers to heating the metal to a certain degree before you start the welding process. It heats up the metal making it easier to perform a more smooth and perfect welding job.

Acorn Welding provides all the technical knowledge, resources, and equipment to its professional aviation welding technicians to avoid any defects and flaws in the welding process. To get in touch with us, click here.