What Is Arc Welding? –[Meaning, Definition and Process Types]

what-is-arc-welding

Arc welding was first discovered around 1800. In the past 200 years, it has undergone successive waves of optimization and renovation. It’s also why several industries depend on arc welding in their processes. Look around you, anywhere from construction sites, to automotive factories, aircraft hangers, marine docks, all the way to workshops.

What is Arc Welding? Arc welding is a welding process that uses an electric arc to create heat to join metals. A power supply generates an electric arc between a non-consumable or consumable electrode and the base material using either direct current (DC) or alternating current (AC).

here’s the complete guide, with everything you need to know!

What Is Arc Welding Used For?

Arc welding utilizes electricity to create a focused energy burst, a lot like lightning. Here’s how this powerful device is used.

To Melt and Join Various Metals

This electric arc is capable of raising the temperature at the point of application to around 6400 degrees.

This far exceeds the melting point of high-carbon steel, which is around 2600-2800 degrees. It’s also beyond the 3000-degree melting point of titanium. 

To Create Pure Welds

The concentrated heat creates a pool of melted metal in the workpiece right away. This allows the welder to join two metal parts together, with or without extra filling.

Applying a shield of inert gas or flux around this metal puddle ensures that the solidifying metal wouldn’t contain impurities.

Related reading: 5 Types of Welding Joints and Their Use – Complete Guide

To Maintain the Mechanical Properties of the Welded metals

The difference between a weld that’s done under the protection of a shield, and another that’s left to the atmosphere, is mainly in their mechanical properties.

The air contains many kinds of pollutants and oxidative agents. Once these reach the weld, it becomes brittle and prone to corrosion.

To Get the Job Done Quickly with a Good Finish

Arc welding is thus capable of performing welds that retain the original strength of the workpiece. A skilled welder would also choose the right arc welding technique. This gets the job done quickly, with top-notch finishing.

An example is working with TIG welders. These devices offer the neatest beads of all, provided of course that the welder has the right level of dexterity and manual skill.

The TIG welds do take a bit more time than MIG, but even with the high precision of MIG, TIG welding is still capable of maintaining the good looks of a workpiece.

Related reading: What´s The Difference Between TIG and MIG Welding?

To Fit Various Work Requirements

The different techniques of welding offer varied benefits for welders. For example, stick welding is great for site work.

MIG is great for intricate work, like auto repairs. And TIG is the jack of all trades, that can work on several kinds of metals.

The power settings on an arc welding machine can be on the lower side, mid-range, or you can get a machine with seriously high power output.

This all depends on the kind of work you do. Some workshops have more than one welding machine to cover all bases.

To Support Different Industries

Arc welding is versatile, aggressive if needed, and gets the job done. It’s normal to see it in construction sites, used extensively in mechanical works, in auto repairs, and even in mega projects. It’s also routinely used in shipyards and for aviation works.     

Being all that powerful; is the biggest advantage of arc welding, but it’s also its main weakness.

Thin sheet metals aren’t particularly operable with arc welding. They’re still manageable, especially with MIG welding.

But it takes a bit more skill to work on gauge steel without warping or penetrating it.    

What Are the Types of Arc Welding?

Arc welding uses one principle, which is utilizing electricity to create significant heat, that it can melt tough metals.

From that main principle, engineers and welders came up with several derived techniques. Each of them solves a welding issue.

 The arc welding method used indoors is necessarily different from that used outdoors. And what fits well for precision work, might not be the best solution for heavy production work.

There’s also the matter of weld placement, type of metal, and workpiece thickness.

The different methods of arc welding could be categorized further according to the electrodes used in the process.

Roughly speaking, there are consumable electrode methods, like stick and MIG. And there are non-consumable electrode methods, like TIG.

The arc welding types could have another parameter for classification, which is their consumable wire feed type. In that regard, there’s manual, semi-automatic, and automatic.   

Here are the basic types of arc welding: 

Stick

Also called Shielded Metal Arc Welding (SMAW), Manual Metal Arc Welding (MMAW), or Flux Shielded Arc Welding.

The stick welding method is one of the oldest welding types. That’s why it appears to be simple, and in a way raw.

The base material is hooked up with the welding machine so that it becomes part of the circuit. The electrode of the stick being the other pole.

Striking the arc doesn’t happen right away, it actually takes a bit of practice, and a movement that mimics striking a match.

Once the arc is set up, the electrode needs to be moved in uniform increments, forward and sideways. The base metal melts under the effect of the heat, and the electrode supplies the required filler.

The electrode composition is often picked according to the base material. It needs to be compatible and provide the best matching with it. This ensures that the join would maintain the original properties of the base metal. 

The shielding of the weld comes from the shield of the electrode. As it melts, the vapor forms a protective cloud around the metal puddle. It also forms a layer of slag on top of the solidifying metal for further isolating it from the impurities hanging in the ambient air.

Related reading: Do You Push or Pull When Stick Welding? Which Is Right?

Stick welding is straight forward and easy to learn. It also allows more flexibility since it doesn’t require any gas attachment and it’s not bothered by the air. That’s why it’s quite common in construction sites.

It’s often used for ferrous metals, which is a bit limiting. However, recent modifications in the welding machines and electrodes allowed the use of stick welding for aluminum, nickel, cast iron, and copper.   

On the other hand, it’s a bit rough and messy. It also leaves a slag layer that needs chipping and brushing off after the work is done.

All-in-all, stick welding is an important technique that any welder worth his salt should master. Actually, when people refer to ‘arc welding’, they often mean ‘stick welding’.   

Metal Inert gas Welding (MIG)

Formally referenced as Gas Metal Arc Welding (GMAW), is pretty much an elegant form of stick welding. It has a more ergonomic handle, that automatically feeds a wire, to act as the filler electrode.

An inert gas flows around the wire/electrode to provide the necessary protection for the welded joint. The weld is often quick, neat, and precise.

MIG welding was originally devised to weld aluminum and other non-ferrous metals, but its ease-of-use soon added steel to its domain.

MIG isn’t needy when it comes to power settings. It often works with constant voltage DC. But it also works well with constant current DC, and even AC.

The setup of MIG welding is clearly far more elaborate than the stick. Plus, it can’t be used outdoors or in draughty rooms.

This limits the usage of MIG to the workshop. It’s portable within that space, so if you happened to work on auto repairs and renovations, a MIG welder would be perfect for the job.   

Flux Core

The real name of which is Flux Cored Arc Welding (FCAW). It’s basically an adjustment for the MIG machine that makes it usable outdoors.

The wire used holds the main difference. The addition of a flux material eliminates the need to connect an inert gas to the welding machine.

This allows welders to use the flux core welding machine outdoors, just like the stick, but with the dexterity offered by the MIG.

Flux core could be used with the inert gas shielding setup as well, which would provide double shielding. It’s not necessary though, and for the sake of portability, it’s often used without. Flux core welding is quick and easy, so it’s not a surprise to see it all around construction sites.  

Tungsten Inert Gas Welding (TIG)

Otherwise known as Gas Tungsten Arc Welding (GTAW), is a different welding technique that uses a non-consumable electrode. The rest of the setup includes a filler electrode and an inert gas source.

Welders trained for MIG or Stick might find TIG welding a bit confusing at first. That’s understandable as TIG welding involves moving both hands around the base metal.

Melting the metal with one hand, and moving the filler electrode with the other.

After a little while, most welders develop a personal style for using these multiple tools. The effort invested in learning TIG welding is rewarded in the ability to do high-quality welds.

These joints rarely need further finishing or hiding out of sight. They really look good.

A TIG welder is versatile and performs well with a wide array of metals. It can handle thin metals well, so it’s often used in domestic objects like bicycles.

The sturdiness of the joins and good quality finishes added aviation and marine work to the specialties of TIG welding. 

Submerged Arc Welding (SAW)

Submerged arc welding doesn’t refer to underwater welding, despite the ‘submerged’ thing. Actually, what is submerged is the metal base. It’s completely covered by granular flux. You might be wondering now how the welder is able to reach to workpiece? There’s no welder in this scenario. 

This is an industrial welding technique. It’s fully automated and the arc is positioned such that it reaches below the flux covering. The protection from atmospheric contaminants is impressive. And the slag layer that forms, soon comes off on its own.

Submerged arc welding is quick, precise, and gives off minimal amounts of smoke. It’s often used for large pieces, in processes where high throughput is needed.   

Plasma Arc Welding (PAW)

This method is a derivative of TIG welding. The main weaknesses of TIG are its slow progression and restricted usage of thin metal sheets. Plasma arc welding employs plasma gas to create a much more focused arc.

This allows for using PAW on thicker metal pieces, as well as automating the process. This naturally boosts the speed of welding, while retaining its prime quality finishes.

Plasma takes versatility even further and offers the extra application of cutting steel sheets. The cuts are often neat and precise, that why there are stand-alone plasma cutting machines.

Plasma arc welding works on various metals like aluminum, titanium, copper, and steel. This is close to the utility range of TIG, but it can’t do magnesium though.

It’s often used for stainless steel applications that can be automated. 

Arc Stud Welding (ASW)

Arc stud welding is a process that provides sturdy fastening of two metallic parts, without the need for drilling holes.

This is also an industrial process that allows a high production rate, plus joints that can’t be loosened or disconnected at the drop of a hat.

Electro-Slag Welding (ESW)

Electro-slag welding is another automated welding process that looks a lot like submerged arc welding. It’s used to perform a symmetric, gap-filling weld, in a single pass. 

The setup is a bit complicated, and so is the principle it works on. However, this is the concern of industrial engineers, and these folks enjoy a challenge!  

How Does an Arc Welder Work?

The arc welding machine is primarily a power source with a couple of cables. The power that comes out of the welding machine is directed to the two poles of the cables. One side is connected to the workpiece, and the other to the electrode.

When the circuit is closed, the resulting confrontation of the electric poles results in an electric arc. The electrode carries the heat generated from the arc to a single point on the workpiece.

This is how the metals and the filler melt, and the weld is subsequently created.

The welders have several settings and a few attachments to optimize their usage. Some are designed to provide a single type of welding, like a MIG welder.

Others, are more versatile and give more than one mode of operations. Some go all the way to working as multiprocess welders

The basic setting on the welding machine is its power capability. The power input of the welder is classified initially into DC and AC. Each one has its uses and applications. 

The voltage of a welding machine decides the length of the arc, while the current controls the amount of heat generated. Most machines are capable of providing constant current or constant voltage.

The polarity of the electrodes is among the most important settings in DC welding machines. The anode, which is the positive electrode, retains most of the heat. This is a good thing when a deep weld is needed, or when the workpiece can’t take the excessive heat.

Reversing the polarity shifts the location of the heat to the workpiece, and allows doing shallow welds and more delicate work. 

Another important setting is the duty cycle. This figure is often given as a percentage, and it dictates how long a welder can work before it needs to take five.

For example, a duty cycle of 60% says that a welder can work for six minutes, then stop the machine for four minutes.

How Arc Welding Works >> Check out the video below:

Is Arc Welding Stronger than MIG?

Before pointing out that MIG is actually a form of arc welding, you might recall that I mentioned earlier that Stick welding is often called ‘arc welding’. Thus, this is a comparison of the muscle power of MIG vs. Stick welding.

The competition is almost a done deal before we even start. MIG was derived from stick welding to handle finer stuff. It doesn’t have the same deep penetration or generous filler deposition as stick welding.

In sheer terms of strength, it’s pretty clear what you’d need to choose for welding a large piece. However, things are as black and white as that. It’s wise to consider other parameters as well.

Welding a small piece wouldn’t require excessive welding power, so the MIG welder and the Stick welder would have a tie. Besides that, in terms of accuracy and speed, MIG gets the round easily. 

Related reading: The 8 Strongest Types of Welds You Should Know

The Advantages and Disadvantages of Arc Welding

Arc welding has been around for about 200 years. It’s been widely used in construction, shipbuilding, and aircraft. In recent times, arc welding found its way to smaller industries.

Even hobbyists and homeowners can use an arc welder nowadays.

All this broad history demonstrates the importance of arc welding in various settings. Here are some of the reasons why it’s widely used, along with a few downsides that come with that usage.

The Advantages of Arc Welding

  • Effective welding of various ferrous and non-ferrous metals
  • Quick welding of large pieces of work
  • Ability to perform precise welds if needed
  • Welding could be done indoors or on-site
  • The welding machines are available at various prices
  • The join maintains the basic properties of the welded materials
  • The shielding keeps the weld pure and free from corrosive agents
  • It can weld two non-compatible metals
  • The possibility of welding underwater or very large pipes

It’s hard to believe that after all these benefits, arc welding could have any shortcomings at all. But here we are, nothing is perfect folks!

The Disadvantages of Arc Welding

  • Arc welding is powerful, so it’s not well suited for welding thin sheet metal
  • It uses plenty of resources compared to other types of welding
  • Welders need extensive training to perform well
  • The machines are a bit complicated and need skills to operate
  • The basic setup of an arc welding workshop could be costly

Related: How To Start & Grow a Welding Business In 11 Steps

Is Arc Welding Easy for Beginners?

Arc welding involves learning about four basic welding techniques, understanding how the welding machine works, and knowing what’s the best usage for each arc welding type.

In addition to that, the need to learn all the safety measures of working in an arc welding workshop.

This is a place where metals get superheated, there’s high voltage equipment everywhere, there’s a risk of explosion, and the torches literally dissolve iron! 

This surely looks like a big chunk, and it could be considered difficult for beginners. However, from my experience, I know that beginners navigate through the various technicalities without much trouble.

Many welders develop their own welding styles soon after they learn the basics. This shows how quickly they acquire the necessary skills, and also, that it’s easy to feel confident enough around these machines. 

The first unsightly beads, and a few accidents with the tungsten needle, could discourage some welders. But, with persistence and diligence, most of these rookie mistakes become fodder for mastery. 

It’s also highly recommended to learn arc welding form the pros. Online videos are awesome and highly informative. But there’s no substitute for direct mentoring when it comes to arc welding.  

Related reading: 11 Common Welding Defects and How To Prevent Them

Conclusion

Professional and beginner welders alike work with arc welding machines. There are so many techniques, and as many settings, to be learned.

This could feel a bit overwhelming. Especially, if one keeps hearing the different welding terms thrown around, without understanding fully what they mean. More importantly, the feeling that an important skill is missing. And hence, an opportunity for business improvement could be lost.

This guide contains everything you need to know about arc welding. So if you plan on learning a new skill or expanding your welding business, this should help you to find your first steps. 

Welding is a field where we are constantly learning new things. New machines are constantly introduced to the market. And with them, comes an increased potential to cover bigger projects. Keeping ahead of the curve means getting well acquainted with the machines, and becoming proficient at how to use them.

You know what they say: the more you learn, the more you earn!

David Harper

David is the Co-Founder and Senior Editor at weldingtroop.com. David's an experienced fitter and tuner/welder who's passionate about helping others develop in life through new skills and opportunities.

Recent Posts