Welding Types and Definitions for Beginners

 This is the first look at welding is a process that turns two pieces of material into one piece of material. Glueing brazing and soldering stick different materials together, but when you weld the separate pieces become a single piece.

 

This is done in two different ways either the materials are made liquid and then solidify together, or the materials are joined by forcing them together with a lot of pressure and sometimes heat.

 

The melting type of welding is called fusion welding and heat or pressure and the method is called solid-state welding.

 

There are lots of ways of doing both of these, let's look at a few of them. Today we'll look at some fusion welding processes because they are the most popular the most transparent way to get material into the liquid state is to heat it and melt.

 

It but you can also use solvents to melt material. You may have done welding and not even known it.

 

When you use PVC pipe cement, you're turning two pieces of plastic into one by dissolving them and letting them re-solidify as one piece.

 

But I have a feeling that you want to know about welding metals so let's look at that melting metals takes a lot of energy and that energy needs to be focused on the small area.

 

We want to meet one of the simplest ways of doing. This is to take a fuel like acetylene and mix it with oxygen.

 

This produces a very hot flame the flame heats up both parts of the metal. We want to join the metal in these parts is called the base metal the base metal of these parts melt and form puddles.

 

 

These two puddles coalesce or run together into a single puddle the welder moves the flame down. The joint and as a puddle solidifies the two parts become an available part many times.

 

It takes some extra metal to make a good joint.

 

In this case, a piece of wire is dipped into the molten metal it melts and becomes part of the weld this metal is called filler metal.

 

It helps make a joint stronger by providing additional material using oxygen and acetylene to weld in this way is called the oxy-fuel gas welding or OFW method.

 

Now electricity is another way to melt metal the most common The type of welding that uses electricity is called arc welding.

 

Now there are three kinds of arc welding that are the most popular these are shielded metal arc welding, or SMAW also called stick welding.

 

There is gas metal arc welding or gmaw, usually called MIG and there is gas tungsten arc welding or gtaw which is called TIG.

 

I will keep calling these stick MIG, and TIG for short all three of these welding processes use a powerful arc of electricity to heat the metal to the melting point.

 

The arc is like a small lightning bolt between the base metal and the piece of metal on the torch called an electrode. Now in stick and MIG welding, the electrode is designed to melt and become filler metal.

 

In the joint and TIG welding, the electrode is made of tungsten you grind. It to a point and you put it in the electrode holder or torch.

 

Now tungsten has a very high melting point and the arc isn't able to melt it the arc dances off the end of the electrode.

 

While it melts the base metal if your TIG welding you want to use filler metal. You add it separately dipping it in the weld pool just like you would with oxy-fuel gas welding a stick welding electrode looks like a little bar of metal about a foot long with a covering on it. You hold a stick electrode and a holder that has a clamp on it a MIG welding.

 

The electrode is actually along with a spool of wire that's usually a little less than a millimeter in diameter the MIG electrode is fed through a tube and comes out when you pull the trigger on the welding gun or torch.

 

Now I should tell you that when you heat metals to the melting point, they tend to react badly with oxygen water vapour and other things in the atmosphere.

 

 When this happens, the weld becomes weak and porous. So it's hardly welding at all.

 

So to keep the weld pure clean and robust a shielding gas is necessary for stick welding. The shielding gas comes from a covering that is all around the electrode.

 

When this covering gets hot, it creates a cloud of shielding gas that protects the weld from contaminants. It also leaves behind a cover called slag that continues to watch.

 

 The weld while it cools when the metal cools this layer slag has to be removed in TIG and MIG welding. The shielding gas comes from a compressed gas cylinder these cylinders store.

 

 The gas very high pressure often thousands of pounds per square inch one of the most common types of shielding gas is argon sometimes mixed with carbon dioxide or other gases and this gas flows.

 

Through a hose and comes out right at the point of the arc.

When you're done, there's no slag or other residue, but sometimes you may need to clean up a little spatter which is tiny drops of metal.

May have stuck to the base metal.

 

Well, that's a quick look at the world of welding if you want to know more just let me know in the comments section.