A Welders Life
by Rob Briscoe
Welding is a good career choice for many people. The welding process is used throughout the manufacturing and maintenance industries. Cars, planes, trains, and toys are made using a variety of welding methods. This article will discuss the welding process and basic welding types. It will also show some of the benefits of each type.
All welding involves heating the materials above their melting point, then joining them with or without filler metal.
The basic methods of welding metal are:
- GMAW (mig);
- GTAW (tig); and
- SMAW (stick) welding.
Mig Welding – GMAW
GMAW welding is usually called mig welding. This type of welding uses electricity to melt the base metals and filler wire. The filler wire is added to the base metal and is consumed during the process. This is usually the easiest welding method to learn and is also the most common type of welding in industry and by home hobbyists. The GMAW process can be used for carbon steel, stainless steel, tool steels, and many aluminum alloys. Mig welding can be performed using a solid wire with shielding gas or with a flux-core wire. Flux-core wire is especially useful when welding in windy conditions, where the shield gas would be blown away. The primary drawback to flux-cored wire is the need to remove the slag between passes. Solid wire with a shielding gas is more common in industry settings.
To weld with a mig welder, a ground is connected to the workpiece and the gun is brought into position, normally about ¼” off the workpiece. The operator feeds the wire and starts the arc by pulling the trigger on the mig gun. The welding current is carried along the wire until it reaches the grounded workpiece. The resulting spark stabilizes into a steady arc which melts the base metal and the filler wire. The weld wire is consumed during the GMAW welding process.
As a manual process, the operator is responsible for positioning the mig gun and adding the correct amount of filler wire.
There is more to the GMAW (mig) welding process than will be explained in this article. However, the GMAW welding process is relatively easy to learn and is normally one of the first types of welding mastered by a new welder.
The GMAW process is also used extensively by robotic welders. In this process, the weld parameters and start / stop points are programmed by the operator or welding technician. Once the robot is programmed correctly, it can make the welds, the same way, every time. This repeatability is the greatest advantage for robotic welding.
Tig Welding – GTAW
The GTAW process is commonly known as “tig” welding. This process is different from GMAW welding because the electrode is not consumed during the weld process. The arc used to melt the metal is produced when the torch (electrode) is brought close to the grounded workpiece. The electrode is made of tungsten, and is not consumed during the welding process. Instead, filler wire is added by the operator, usually by hand. Robotic GTAW (tig) welders are available, but are not as common as the GMAW robot welders. GTAW welding is more precise, clean, and controllable than nearly all other welding methods. It is commonly referred to as “white glove” welding. GTAW welding is less forgiving of oils, scale, and other contaminants in the weld area. The parts to be welded and the filler metals must be clean. The parts should also fit close, with any gaps kept as small as possible.
To tig weld, the operator will bring the electrode close to the grounded workpiece. In one common process, the operator uses a foot or thumb controller to control the arc intensity by adjusting the amperage. Once the tungsten is close to the workpiece, the operator starts the arc with the controller slid up (thumb control) or by pressing the toe side of the foot controller. Once the arc is stable, back off the amperage. The parts are heated by this arc. Once the base metals each have a good puddle of molten metal, dip the filler wire into the puddle. This will melt the filler wire into the base metal and fill the area between the base metals. Move the arc to melt the base metal, and dip the filler wire into the puddle again. This dip-dip-dip of the filler wire gives the GTAW (tig) process the common “stacked dimes” look.
The GTAW process requires the operator to control more parameters than the GMAW process, and is considered to be more difficult. Like anything else, practice is required to master GTAW welding.
Stick Welding – SMAW
The SMAW process is more commonly known as “stick” welding. Like the GMAW process, the current is carried by the consumable electrode in the form of a welding rod. The welding rod is consumed during the welding process. This process is ideal for use outdoors or in conditions that would blow the shielding gas away if GMAW or GTAW processes were used. The equipment is simple to purchase and operate and is usually inexpensive. A solid flux is melted during the weld process. The purpose of the flux is to protect the molten metal while it cools. If the volt and amp settings are correct, the flux coating (slag) is normally easy to remove, and will often fall off by itself.
To start the arc with stick welding, a welding rod is placed in the electrode workholder. The workpiece is grounded. The welding rod is touched lightly to the workpiece in a manner similar to striking a match. The resulting arc is stabilized when the operator achieves the correct distance between the welding rod and the workpiece. This is where operator skill comes into play, as this gap should remain the same, even though the welding rod is being consumed and growing shorter during the welding process. A supply of welding rods will be required, as they are usually consumed quickly.
A note on safety: Some welders will guide the welding rod with their gloved hand instead of using only the electrode holder. Doing this may allow the welding current to pass through your body instead of the welding rod. This practice is not safe and is not recommended.
Overall, SMAW, or stick welding is considered to be more difficult than GMAW welding. However, the advantage of being able to weld outdoors and low cost of equipment and supplies makes this a popular type of welding. With practice, this type of welding can be mastered and used successfully on the farm or factory.
Is a Career in Welding for You?
We have only discussed three of the main types of welding processes. There are approximately 100 types of welding processes. The three types presented here cover about 90% of arc welding used in production, fabrication, and repair industries.
A person interested in becoming a welder, either for hobby or as a career should consider one or more of the primary welding processes. Further, it is always a good idea to pursue welding certification courses and tests to pass AWS D1.1 standards. This is a very good way to prove the quality of your welds, both to yourself and to your employer.
So, is a welding career for you? Chances are, if you already have a hobby involving cars, you have needed to weld something. As long as there are parts made of metal, a welder will be required. So why not make money doing something interesting?