Last Updated on June 10, 2020 by Gary Hargrave
If you are a professional welder or completely new to welding, chances are you might have at least heard about the term Arc Welding. Basically, it’s the most common welding technique out there that has been practiced since the inception of the term “welding” itself. In this article, we’ll go over all the arc welding basics that you need to be aware of.
Arc Welding is a common welding process which basically represents a diversified range of welding techniques that are carried out thorough supplying current to heat & melt the weld metal using an electrode and consequently produce a strong joint over the weld area.
The electrode of Arc Welding can be both consumable and non-consumable. Now, there are over 10 to 12 different types of Arc Welding techniques, among which 7 of them are widely used. They are:
- Shielded Metal Arc Welding
- Flux Cored Arc Welding
- Gas Metal Arc Welding
- Gas Tungsten Arc Welding
- Submerged Arc Welding
- Carbon Arc Welding And,
- Plasma Arc Welding
Apart from these, there are also some other types including Electroslag, Stud and Electrogas Arc welding which are practiced over several different areas. Now let’s head over to all the common type of works that are mostly carried out by Arc Welding:
Topics Covered in This Article
What Is Arc Welding Used For?
The application of Arc Welding is so versatile because of its cost efficiency and ease of use. In fact, nearly all the manufacturing industries and their production units primarily use Arc Welding over their joining and fabricating processes. Among them, Construction, Automotive, and Aerospace are the most notable areas where Arc Welding is frequently performed.
How to Arc Weld?
Now, Arc Welding is basically performed by two methods. One is by using a consumable electrode and the other is through a non-consumable electrode.
The former is used in the four out of seven techniques of Arc Welding which includes Shielded Metal Arc Welding, Gas Metal Arc Welding, Flux Cored Arc Welding, and Submerged Arc Welding.
On the other hand, Gas Tungsten Arc Welding, Carbon Arc Welding, and Plasma Arc Welding use non-consumable electrode instead.
As Arc Welding consists of several different techniques to form a joint, you got to know about the technical differences lies among each of those techniques. But before that, let’s jump into some of the basics of Arc Welding that are typically used in all the processes.
There are basically four sequential steps by which Arc Welding is performed. They are:
- Step 1: Forming an Arc: Formation of an arc is the first process in performing Arc Welding which is established in between the work-piece and electrode.
- Step 2: Producing a weld bead: Weld bead is the sign that is being seen over the joint area which consists of the combination of molten work-piece and electrode.
- Step 3: Weld bead finishing: This is done by performing some weaving techniques right over the point where the welder intends to finish the weld bead. This includes zigzag, circular, square and figure 8 techniques.
- Step 4: Removing leftover lag: After completing or drawing a full pass or weld line, you have to clean all leftover flux material from the area so that the weld only contains molten part of the work-piece and electrode.
Now, Arc welding requires some essential gears and tools which are needed to successfully perform the welding task. Let’s learn about them:
Welding power supply: Arc welding can be performed by both AC and DC power. DC power is supplied by electric motor run generators whereas AC power is supplied by transformers.
Cables: Welding cables essentially help to supply electricity from the power supply to the electrode holder and all the way up to produce an Arc through the supply of current from the electrode.
Electrode Holder: Electrode Holder physically helps to hold the electrode in hand while performing the welding task. They also differ in sizes and amps depending on the type of holding equipment.
Electrodes: Now, this is the most crucial tool of the overall welding process which is basically an alloy or metal rod. Electrode is the main tool that supplies current to form an arc. As stated earlier, electrodes are basically of two types. One is consumable and the other is a non-consumable electrode.
Now they both can also be categorized into two sub-types which are bare and coated for consumable electrode and tungsten or graphite/carbon for a non-consumable electrode.
Hammer: The hammer is also another essential tool which is basically called the chipping hammer. It basically removes welding slag through striking.
Wire Brush: Wire brush is required to simply clean up the surface before welding.
Hand Screen: Hand Screen is very essential to protect your eyes from being damaged while observing the welding task
Safety Clothing: As with the hand screen, this safety cloth helps the welder from having any potential sprinkle of molten metal or fire.
Now arc welding, similar to that of other welding processes also requires adequate safety measures before and while you’re performing the actual task. Let’s learn about all of them in brief:
Be Cautious about Electric Shocks and Getting Burnt: Welding is an electricity oriented process that can potentially damage and harm your skin if you aren’t conscious and defensive about this issue. So make sure to never touch the work circuit or electrode in bare hand and keep a moderate voltage of electricity typically between 80 to 120 volts for avoiding such accidents.
However, also try to avoid touching the work-piece that has recently been welded because it still remains hot enough to burn your skin after a while.
Protection from UV lights: UV lights can presumably damage your skin and eyes if approached directly. In this case, you got to wear long-sleeve jackets or clothes for protecting your full body parts.
Never breathe fumes: Fumes can be dangerous if the work-piece is galvanized or coated because it emits toxic air which can be a serious health concern for you. Just use a ventilation system or a fan to keep those gases away from you.
Moderate use of welding equipment: Over-using your welding equipment can make them overheat which increases the risk of potential accidents and also make them obsolete or unusable.
Keep flammable items and gas cylinders away from the welding area: welding produces an incalculable amount of sparks and flames that can presumably hit gas cylinders which creates the risk of a potential explosion. So keeping those aside or in a safe position can definitely help.
Now let’s learn about two of the welding techniques along with each of their subcategories:
Consumable Electrode Technique
Shielded Metal Arc Welding: Well this process uses a consumable electrode and the current is supplied from a welding power supply in order to produce an arc between the work-piece and electrode which consequently performs the weld by melting them at high temperature.
Flux-Cored Arc Welding: This process can be both fully automatic and semi-automatic. The main part which only requires here is a constant power supply that will go through the consumable electrode to produce the arc. The electrode also contains flux material along with external shielding gas which prevents the welding from metal and atmospheric contamination.
Gas Metal Arc Welding: Now this process also known as MIG welding which is basically performed by continuously feeding a solid wire that forms the weld pool. Besides, shielding gas is also used to protect it from contamination.
Submerged Arc Welding: As the name suggests, this welding process is performed under a blanket of flux material that removes any potential means of contamination which also uses a tubular electrode that is continuously fed while performing the task.
Non-consumable Electrode Technique
Gas Tungsten Arc Welding: In contrary to the other types, this popular welding process uses a non-consumable tungsten electrode. As a result, this process may sometime require a filler metal to cover the absence of a consumable electrode while at the same time, shielding gas is also used to protect from contamination.
Carbon Arc Welding: Now this process basically uses a non-consumable carbon or graphite made electrode instead of a tungsten electrode for carrying out the combining task. In this case, the temperature may rise as high as 3000-degree Celsius that consequently melts the welding metals.
Plasma Arc Welding: The last among all the categories, Plasma arc welding is basically similar to that of gas tungsten arc welding where the difference lies in the position where the electrode is placed. In plasma welding, the electrode is basically positioned inside of the welding torch body that keeps it away from the shielding gas coverage. Besides, the high temperature of plasma subsequently results in the fusing of the welding materials.
Things To Remember During Arc Welding
Apart from all the info and techniques we have covered in this guide, Arc welding also requires you to be aware of some other areas that will be quite essential at the time of performing the welding task by yourself. So let’s explore them:
Preparation of the welding metal: We all know that the presence of some unanticipated substance on the welding metal or work-piece can create metal or atmospheric contamination as many of them emit chemical gases that can make the finished weld pool vulnerable to a diversified range of weld porosity. For this reason, any potential substances like paint, rust or grease should be removed from the weld metal by using an abrasive tool or brush which will remove the potentiality of occurring such sort of situation.
Attachment of clamps: Attachment of clamps over the work-piece and in the ground area will help the overall task to be performed under a stabilized manner as clamping duly helps to secure the position of your welding materials which also eases the task. However, you should also be aware of removing those contamination occurring substances such as paint or grease before attaching the clamps.
Choosing the accurate welding rod: There is a very common question comes into any new welder that is, “what’s the accurate size of an electrode should I use?” Well, the thing is electrode comes in several different sizes which commonly attribute a numerical value, named as 6010 to 6013, 7018 and 7024. Now among these, 6010 can be deeply penetrated while the 6013 version is less penetrable because of its durability. Besides, you can also choose 7018 for a strong appearance of the weld bead.
Correct amperage settings: As with every welding process, the amperage setting is a crucial thing to consider in order to ensure proper and safe welding of an area. However, this thing also depends upon the size of your electrode that you’re going to use. A rough estimate can be to use 75 to 125 amperage of current with a 6010 rod which is 0.125 inches in size. On the other hand, a 7018 rod with 0.15 in size can require as high as 220 amperage of current supply.
Accurate welding rod angle: Now, the knowledge of maintaining a correct rod angle is very essential to prevent any potential slag overtaking of the welding rod. Besides, it’s the technique of preventing any inclusions to occur inside the welding work which can be easily prevented if a certain degree of angle is maintained. In this regard, you can position your welding rod vertically around 10 to 12 degree while drawing a straight line of the weld bead.
Removing of remaining slag: As you may already be aware of the issue that, right away after you’re done with drawing a welding line, you’re highly responsible to clean out any remaining slag out of your welding metal as it may create post welding contamination or left a porosity oriented material mixture that may potentially ruin your overall task. In this case, you can remove the slag by using an effective and abrasive brush right away after each line and also, be sure to wear safety apparels which will protect you from the toxic gas usually passes out from these substances.
Proper Arc lead angle: You got to be aware of the fact that a big or full-size electrode will produce an excessive arc length between the weld bead and the electrode which consequently result in higher heat and over-penetration of the area. While conversely, as the electrode gets shorter, it’s going to smaller the length of that arc. Hence, you have to keep an appropriate lead angle of the arc. Besides, keep the lead angle in a stabilized manner other than reducing it while beginning the welding task.
Accurate Arc length: Lastly, in reference to the previous one, the maintaining of a proper arc length is crucial to ensure a successful welding of any area. In this regard, you can periodically be aware of the sound which is continuously coming out as a result of the welding operation. Any unusual or cracking sound is a bad sign of inaccurate arc length.
We believe the arc welding basics that we’ve covered in this whole guide is sufficient enough to make you aware of all the essential info regarding arc welding.
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