What do a boat, trailer, car and skyscraper have in common? When made with steel, they're held together by welds.
Welding happens when you use various means to connect two pieces of metal, but did you know that there are actually three different types of welding applications? Let's take a closer look at how each one works, and where you might find them.
If you've ever seen a blacksmith hammering away on a piece of red-hot steel, you're already familiar with the basics of welding. Forge welding has been around for thousands of years and consisted of a blacksmith or metalworker heating two pieces of metal until both were red-hot. Then, they could place the two pieces together and hammer them until they welded together.
Until the 19th century, when we started to explore the possible use of electricity and electrodes in the shop, forge welding was the only way to connect two pieces of metal. Today, we've got three different types to choose from, though some welding applications are more challenging than others.
Two of these three methods fall under the blanket category known as Arc Welding because they rely on electricity to generate the high temperatures necessary to melt metal. The electric arc creates temperatures higher than 3,500° C — more than enough to melt everything up to and including high carbon steel.
First, we have metal inert gas welding, also known as MIG welding. Many consider this type of welding as the easiest to learn, making it perfect for beginners. MIG welding rigs automatically feed a consumable electrode through at a constant pace, while maintaining a steady charge. The gas — usually argon or another inert gas — protects the weld as it solidifies by preventing it from coming into contact with oxygen in the atmosphere.
This setup can be problematic when it comes to outdoor welding because there is nothing to prevent the inert gas from blowing away. You can remedy this possibility by using flux-core wire. This wire has a core of flux that turns to gas as it comes into contact with heat. It doesn't look as nice as traditional MIG welding, though — plus that flux-core wire is a bit too expensive to be practising with!
Applications for MIG Welding include:
Next, we have tungsten inert gas (TIG) welding. Like MIG welding, TIG uses an inert gas — usually argon — to shield the welds while they solidify, but that's where the similarities end. Unlike MIG welding, TIG uses a non-consumable tungsten electrode to create the circuit that allows for welding.
TIG welding is more difficult to learn because, in addition to handling the tungsten electrode, you also have to manage the torch, the wire which you need to feed manually, the speed at which you're welding and the amount of current you're applying.
TIG welding is popular in the aerospace and automotive industries because it gives a skilled welder the tools necessary to create incredibly clean and strong welds. It gives them a higher degree, which is essential if you're building something that's going to fly at 35,000 feet or head into orbit. This style of welding can create spacecraft to woven wire baskets that are strong enough to hold just about anything.
Applications for TIG Welding include:
Sometimes, you don't need a welding rig to connect two pieces of metal. Oxyacetylene welding uses a flame torch to heat the metals and their melting points before joining them together. Instead of using an electrode to generate heat, the torch burns a combination of oxygen and acetylene gas that, when combined, can reach temperatures of up to 3,480° C, which is hot enough to cut steel.
Gas welding is popular because it's easy and provides fantastic flame control with relatively inexpensive equipment. Unlike welding equipment, you can also use an oxyacetylene torch for cutting, though it isn't as neat or precise as a plasma cutter or other similar equipment.
Applications for Gas Welding include:
Also known as shielded-metal arc welding, stick welding dates back to the 1930s but is still in use today. It earned its name from the replaceable "stick" electrode that works as both the electrode and the filler material. It's simple and creates some of the strongest welds in the world. Instead of having an additional tank of inert gas, like you'd find in MIG and TIG welding, the stick is dipped in flux that, when heated, becomes a gas cloud that prevents oxidation.
Without the need for an external gas tank, skilled welders can handle stick welding anywhere — in wind or rain or even on dirty surfaces. It's also easy to swap out the electrodes, making stick welding more versatile for connecting all sorts of metals. It might sound easy, but stick welding is among the most difficult skills to learn.
Applications for Stick Welding include:
Welding, whether you're using MIG, TIG, Stick, Gas or some combination of the four, they all have one thing in common — it's all about using heat to connect things. Welding applications make an appearance in nearly every single part of our modern world, from the buildings you live and work in to the cars you drive and the ships you sail. The science behind it might not be as complicated as you think, but it's vital to keep our world connected — both figuratively and literally.
Megan Ray Nichols is a science writer by day & an amateur astronomer by night (at least when the weather cooperates). Megan is the editor of Schooled By Science, a blog dedicated to making science understandable to those without a science degree. She also regularly contributes to Smart Data Collective, Real Clear Science, and Industry Today. Subscribe to Schooled By Science for the latest news.