Flux

Flux is the material used for coating the electrode. It is an essential component in welding processes as it serves multiple purposes.

What is Flux?
Flux is a chemical substance that is used to clean and protect the surface of the base metal during welding. It is usually in the form of a powder or paste and is applied to the electrode or the welding area.

Purpose of Flux
Flux plays a crucial role in the welding process by performing the following functions:

1. Cleaning: Flux helps to remove impurities, such as rust, dirt, and oxides, from the surface of the base metal. These impurities can hinder the welding process by preventing proper fusion between the base metal and the electrode. Flux helps to create a clean surface for a strong and reliable weld.

2. Degassing: Flux also helps to release gases that are trapped in the base metal. During welding, high temperatures cause gases, such as hydrogen and oxygen, to be released from the metal. These gases can cause defects in the weld, such as porosity. Flux helps to remove these gases and prevent defects.

3. Protection: Flux acts as a protective layer on the surface of the weld. It creates a barrier that prevents atmospheric gases, such as oxygen and nitrogen, from reacting with the molten metal. This protection is crucial as these gases can cause defects in the weld, such as oxidation and embrittlement.

4. Stabilization: Flux also helps to stabilize the arc during the welding process. It helps to control the heat transfer and prevent excessive spatter. This results in a smoother and more controlled welding process.

Types of Flux
There are different types of flux available, and the choice depends on the specific welding process and the base metal being welded. Some common types of flux include:

- Rutile Flux: This type of flux contains titanium dioxide and is commonly used in shielded metal arc welding (SMAW) processes. It provides good arc stability and weld appearance.

- Basic Flux: Basic flux contains minerals such as calcium fluoride and calcium carbonate. It is used in processes like submerged arc welding (SAW) and flux-cored arc welding (FCAW). Basic flux provides excellent cleaning and deoxidizing properties.

- Cellulosic Flux: This type of flux is used in SMAW processes and contains cellulose materials. It provides deep penetration and is commonly used for welding thick materials.

In conclusion, the material used for coating the electrode in welding is called flux. Flux performs multiple functions such as cleaning, degassing, protection, and stabilization during the welding process. The choice of flux depends on the specific welding process and the base metal being welded.