Types of Arc Welding

What is Arc Welding?

Arc welding uses intense heat to melt metal pieces together, fusing materials together as they cool in one of the most reliable and permanent metal joining processes currently in practice.

Artisans throughout history used heat-based techniques to join metals together. In recent years, metalworkers have incorporated inflammable gases like oxygen and acetylene to create intense, focused heat with torches, allowing greater precision in metal joining. Recent years have also seen the growing use of electricity as a heating technique, further improving the process’s safety and efficiency.

Most metals conduct electricity well, becoming extremely hot and malleable soon after exposure to high-frequency current. This process allows very small conduction points, which translates to greater precision than other welding methods like forging or oxy-fuel welding.

Arc welding creates precise welds in a variety of conditions. What’s more, their tools’ ability to work on small conduction points renders them more portable and reliable than other welding tools. Recently, arc welding has split into a variety of different techniques, which we’ve outlined below:

Arc Welding Types and Applications

  • Arc welding uses AC or DC current to create electrical arcs between electrodes and base materials, fusing metals together at the point of contact. Arc welders may also employ shielding gases to protect the weld from oxygen or water vapor exposure. Workers use this process with both consumable and nonconsumable electrodes.
  • Flux-cored arc welding (FCAW) uses flux to keep metal surfaces clean during fusion, as impurities can weaken a weld or cause it to fail. The flux within the electrode tube may also create a shielding gas when heated, protecting the weld during fusion.
  • Gas metal arc welding (GMAW) provides the inert shielding gas (usually CO2) from an external source in the welding gun rather than the electrode tube. Industrial welding applications typically rely on GMAW.
  • Gas tungsten arc welding (GTAW) uses inert gases like argon or helium for shielding, and it creates the weld with nonconsumable tungsten electrodes. This process also sometimes uses filler metals, but other methods (such as with autogenous welds) do without them. GTAW conducts constant electricity through gas and metal vapor plasma created by the process’s intense heat. This type of welding works best with stainless steel and nonferrous metals.
  • Plasma arc welding (PAW) incorporates shield gas similar to GTAW, but it instead forces manufactured plasma through a copper nozzle at nearly the speed of sound and at temperatures reaching 50,000°F. The ionized gas conducts electricity and also shields the process.
  • Shielded metal arc welding (SMAW) manually uses a flux-covered consumable electrode that disintegrates and vaporizes to create shielding gas and slag, protecting the weld from impurities and the external environment. Because of this method’s portability and versatility, arc welders use it for a variety of applications.
  • Submerged arc welding (SAW) covers the contact point in welded materials using granulated flux fed from a hopper. The flux submerges the weld pool (where metal fusion occurs) and the consumable electrode wire as they travel along the weld’s length. This process creates filler metal, a weld, and a protective slag covering in one continuous movement.

Pros and Cons of Arc Welding

Each arc welding method has its advantages and disadvantages.

Welding’s use of electrical currents at high temperatures may result in burns or UV exposure to employees, and toxic gases build up in improperly ventilated facilities. The high-frequency electricity used in arc welding may also affect pacemakers.

But with the right equipment and for the right application, arc welding’s advantages outweigh its risks.

Arc Welding

Strengths:

  • Portable equipment
  • Strong welds with a variety of different metals

Considerations:

  • Moisture in welds create embrittlement
  • Not shielded

FCAW

Strengths:

  • No inert gas at risk for disbursement
  • Well suited for outdoor use and construction
  • Uses all positions in the process
  • Easy to learn and operate

Considerations:

  • Creates smoke
  • Creates fumes
  • May result in porosity
  • Relies on expensive filler material

GMAW

Strengths:

  • Eliminates slag
  • Deeply penetrates welds

Considerations:

  • Not intended for thin materials
  • Reliance on shielding gases creates more cumbersome processes

GTAW

Strengths:

  • Greater control
  • Welds nonferrous metals

Considerations:

  • Difficult to master
  • Complex processes

PAW

Strengths:

  • Works with nearly all metals
  • Creates deep welds

Considerations:

  • Complex processes require highly trained operators
  • Variables require a controlled environment
  • Expensive

SMAW

Strengths:

  • Portable
  • Versatile
  • Works in any position
  • No inert gases needed
  • Easy to learn

Considerations:

  • High spatter risk
  • Creates porosity
  • Poor fusion
  • Shallow penetration

SAW

Strengths:

  • Creates strong welds
  • Creates deep welds

Considerations:

  • Not very portable
  • Expensive

A Full Suite of Electric and Plasma Arc Welding Solutions

Welding has come a long way since its first use a century ago. The variety of different processes and custom capabilities it offers renders it useful for any industry that relies on joining metals together.

 

Industrial Alloy offers a broad spectrum of welding services for clients across many industries. Contact us today to see how we can engineer a welding solution for you.

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