Difference between Arc Welding and Gas Welding


Welding is a process of melting and joining different types of materials together. There are several types of welding processes available that are used based on the types of materials being joined or melted. Two most extensively used types of welding are arc welding and gas welding. The fundamental difference between arc welding and gas welding is that arc welding uses electric current to produce heat for joining of metals, while the gas welding uses flammable gases to produce heat for welding process.

Read this article to learn more about Arc Welding and Gas Welding and how they are different from each other.

What is Arc Welding?

Arc Welding is a welding process in which an electric arc created between the electrode and the base metal is employed to supply the necessary heat for melting down the intended surfaces of the workpiece for coalescence formation.

Arc welding is a type of electric welding that uses a welding power supply machine setup to create an electric arc between a metal stick (called electrode) and the job to melt the metals at the point of contact. The greatest advantage of arc welding is that it can be done using either DC supply or AC supply, and a consumable or non-consumable electrode.

The process of arc welding is based on the principle that when an electric current is passed through an air gap from one electric conductor to another, an electric arc is produced which generates a very intense and concentrated heat. This heat is then used for melting and joining the metal pieces.

What is Gas Welding?

Gas Welding is a non-electric welding process in which a flame is obtained by the combustion of a gaseous fuel with oxygen supply to produce the heat required for joining metal pieces. This heat is used to melt the surfaces of workpieces which are held together to form a joint. The chief advantage of the gas welding process is that it does not require electric power supply for joining two metal pieces.

Gas welding is applicable for both electrically conductive and non-conductive metals. Here, two cylinders are used; one contains gaseous fuel such as acetylene, propylene, etc. and another cylinder contains oxygen. Gas welding is best suited for thin plates and sheet metals only.

Differences between Arc Welding and Gas Welding

The following table highlights several differences between arc welding and gas welding −

S. No.

Arc Welding

Gas Welding

1.

In the arc welding process, an electric arc is created to produce the required heat for fusing the base metal for coalescence formation

In gas welding, combustion of gaseous fuel with oxygen is used to generate the required heat.

2.

Arc welding can only be used for the metals which are electrically conductive.

Gas welding is equally applicable for both electrically conductive and non-conductive metals.

3.

Electric arc welding requires availability of electric power supply for its operation.

No electric power supply is required in case of gas welding.

4.

In case of arc welding, no cylinder containing fuel and oxygen is required.

In case of gas welding, two cylinders are employed, one for gaseous fuel such as acetylene, propylene, etc. While another is required for containing oxygen.

5.

Arc welding process requires shielding of the arc and the weld bead which is provided either by flux coating of the electrode or some inert gas.

No shielding is provided in case of gas welding process.

6.

As the arc temperature is very high, the temperature of the core is about more than 6000 °C. Therefore, arc welding can be used for joining of metals having high melting point.

Temperature of the gas flame is comparatively low, about 3500 °C. Therefore, gas welding cannot be used for welding of the metals having very melting point.

7.

The electric arc has a narrow cross-sectional area. Therefore, it reduces the width of weld bead and heat affected zone.

The area of cross-section of the gas flame is relatively wider. Therefore, it results in wider weld bead and heat affected zone.

8.

The high temperature and narrow electric arc increases the heat density, which results in quick fusion of metals.

The lower temperature and wider gas flame result in less heat density. Thus, gas welding requires more for the welding process, which makes it uneconomical.

9.

Arc welding can be used for joining thicker components.

Gas welding is suitable only for thin plates and sheet metals.

10.

Arc welding has inherent arc cleaning, due to flow of avalanche of electrons.

In gas welding process, no arc cleaning takes place. Hence, the base metal requires cleaning prior to welding.

11.

Arc welding is not suitable for heating, cleaning, cutting, etc.

In addition to the joining of metals, the gas welding can be used for heating, gas cutting, brazing, soldering and cleaning, etc.

Conclusion

Both gas welding and arc welding are general purpose welding processes. The most significant difference between the two is that arc welding is a type of electric welding, i.e. it needs an electric power supply to work, while gas welding is a non-electric welding process and no electric power supply is required.

Updated on: 11-Jan-2023

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