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If you are searching for “what is arc welding” this post should help! When it comes to arc welding, there is intense heat that is needed in order to melt the metal, which is done by an electric arc.

What Is Arc Welding?

Arc welding happens to be a process that is used to join metals together. When intense heat is applied the metal joint that made between the two parts will be melted and caused to mix together using a molten filler metal. When it cools and hardens, a strong bond is made between the metals. Because this causes the metals to mix, a final weld will have the same strength of the metal parts. This is actually a big contrast from non-fusion processes such as brazing or soldering, where the physical and mechanical properties of the metals can’t be mixed at the joint.

The arc is then formed between the electrode and work which is done mechanically or manually and guided along the joint. The electrode can be a rod/wire that will conduct the current as well as melts and then supplies the metal to the joint or it can be a rod that just carries the current between the work and the tip. Most welding that is done in manufacturing of steel will use the rod/wire electrode.

Basic Circuit for Welding

Basic arc circuits will have a DC or AC power source that is fitted with the needed controls and will be connected by a work cable to the part and a hot cable to an electrode holder which will create electrical contact with the welding electrode.

Then an arc will be made across the gap whenever the electrode tip and energized circuit touch the part and is pulled away but stays in close contact. This will produce a temperature of around 6,500˚F at the tip. This type of heat will melt the electrode and base metal which produces melted metal which is called crater. The crater will harden after the electrode has been moved down the joint. This causes a welding bond.

Arc Shielding

Joining metal together requires much more than just moving electrodes down a joint. Metals that are at high temperatures will often react chemically with air elements such as nitrogen and oxygen. Whenever the metal has become a molten pool and it touches the air, nitrides and oxides will destroy the strength of the weld. So, most arc welding processes will have a covering for the arc and the metal using slag, vapor or gas. This is arc shielding. The shielding is what minimizes or prevents contact of air to the metal. Shielding can also improve the weld. For instance, granular flux will add deoxidizers to the welded joint.

The arc is a complex thing. Having an in-depth understanding of the physics is not really needed for a welder, but having knowledge of the characteristics can be quite useful.

Nature of the Arc

Arcs are electrical currents that flow between electrodes through ionized gas. Negatively charged cathodes and positively charged anodes will create the intense heat of the arc. The positive and negative ions are then bounced off each other within a plasma column at a fast rate.

When it comes to welding, arcs don’t just provide heat that is needed to melt the base metal and the electrode, but in the right conditions it can transport melted metal from the electrode. There are many mechanisms that can be used to metal transfer. Two of the more common ones are:

Spray Arc

Spray Arc which is where a drop is ejected from the metal at the electrode using an electric pinch which sends into the melted pool which is perfect for overhead welding.

Surface Tension Transfer

Surface Tension Transfer which is where a drop of metal touches the melted pool and then is drawn into the electrode using surface tension.

Arc welding Process

If the electrode is consumable, then the tip will melt from the arc heat and the melted drops will be detached and put on the part through the arc column. Any type of arc welding system where the electrode has been melted off to become a weld will be called metal arc. When it comes to tungsten or carbon (TIG) welding, there will be no melted drops that are forced through a gap and into the part. Filler metal will be melted into the joint from a separate wire or rod.

Most of the heat that is made from the arc will be transferred into the weld pool. This will produce higher efficiencies for thermal areas and will narrow the heat affected zones. Because there will need to be an ionized path in order to create electricity in the gap, switching on the current using an electrically cold electrode will not create the arc. The arc has to be ignited and this is done by create a high voltage to create a discharge. It can also be done by taking the electrode and touching the part and then removing it as the metal starts to heat up.

Arc welding can be done using AC or alternating current or DC or direct current with the electrode being negative or positive. The current choice as well as polarity will actually depend on the whole process, the metal that is being welded, the atmosphere for the arc, and the type of electrode.

Arc Welding Services In Mesa

Our team of welding pros at Cliff’s Welding can help you with your arc welding needs.  Our team specializes in stainless steel, aluminum, cast iron and mild steel welding and uses TIG, ARC. and MIG, welding For more information about our welding services please give us a call at 480-832-0570.