The Science Behind Welding

By Megan Ray Nichols

When you want to join two things together, you have a lot of options depending on the two materials. If you attach paper to cardboard, you can grab a bottle of glue. If you stick plastics together, epoxy is your go-to adhesive. If you try to attach two different pieces of metal, glue won’t cut it. That’s where welding comes in. Let’s take a look at the science of welding, as well as the different types of welding and how they work.

The Science of Welding

The science of welding depends on the type of metals you want to join, as well as the kind of filler material you use to attach the pieces. The most common type of welding is known as arc welding, which gets its name from using an electrical arc to melt both the metals and the filler to create a solid connection or joint between the two.

Start by attaching a grounding wire to the welding material. Then an electrode gets attached to the piece you weld and an electrical arc is generated between the two points, creating a high-temperature area that melts the metal and the filler, creating a uniform joint. Welding is tricky because you need to continuously feed the filler into the welding joint at an even rate to create a uniform weld.

Now that you understand the basics of welding, let’s take a closer look at the different types of welding, including the common less common options. There are 30 different types of welding, ranging from simple to complex.

MIG – Gas Metal Arc Welding

MIG welding is a type of arc welding that uses a shielding gas to reduce the combustibility of the materials. This type of welding reduces waste because it uses a high-efficiency electrode that creates cleaner welds. MIG welds are usually found in the automotive, industrial, robotics and maritime industry.

TIG – Gas Tungsten Arc Welding

TIG welding, also known as heliarc welding, uses a tungsten electrode that can be used with or without a filler rod to melt two metal pieces together. Like MIG welding, this style also uses an external gas supply — most commonly a mixture of helium and argon. You’ll usually find TIG welding in the aerospace industry, water pipe joints and motorcycle manufacturing.

Stick – Shielded Metal Arc Welding

Stick welding, or Shielded Metal Arc welding, use a combination filler rod and metal electrode to melt the filler material and the metal joint at the same time, creating a uniform connection between multiple pieces of metal. Stick welding works on rusty or old metals where MIG or TIG welding wouldn’t work. You also don’t need any shielding gas to complete a stick weld.

RF (Radio Frequency) Welding

Instead of using an electrical arc like the previous three, radio frequency welding uses high-frequency radio waves to heat and melt two surfaces together. This type of welding isn’t typically used on metal though. Radio waves don’t get hot enough to melt metal, but they are capable of melting plastics. RF Welding is similar to the process of microwaving food.

Flux-Cored Arc Welding

Flux-cored Arc welding is similar to MIG welding in that you use an electrical current, but instead of a solid electrode, the contact point is a hollow tube full of flux. When paired with shielding gas, this flux serves to protect the welding joints from oxidation. Shielding gas isn’t necessary though, which makes flux-cored arc welding ideal for windy outdoor environments where shielding gas would blow away.

Electron Beam Welding

Electron beam welding uses a stream of high-velocity electrons like a laser to melt the materials. Instead of heating the base and filler materials separately, the beam of electrons can melt and merge the materials. This is an ideal style of welding for dissimilar metals, or items of varying thicknesses.

Atomic Hydrogen Welding

For materials that don’t bond easily, like tungsten, atomic hydrogen welding creates temperatures up to 3,000 degrees C, creating a cohesive bond. This style of welding was invented after Irving Langmuir discovered atomic hydrogen — putting two tungsten electrodes together inside a hydrogen environment triggers an explosion, welding the toughest metals together.

Plasma Arc Welding

Plasma arc welding is similar to TIG welding but the plasma arc adjusts easier and can be used in three different operating modules from microplasma at less than 15A, to medium current up to 200A depending on the needs of the job.

The Science of Welding

Welding might seem simple, — you put two pieces of metal together and heat them until they melt — but it’s as much an art as it is a science.

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