plz give me information about electrodes used in arc welding...?

Arc welding is a welding process that uses a power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. The electrode, also known as a welding rod or filler rod, plays a crucial role in the arc welding process.

There are several types of electrodes used in arc welding, each with its own characteristics and applications. The most commonly used electrodes in arc welding are as follows:

1. Shielded Metal Arc Welding (SMAW) Electrodes:
SMAW electrodes, also known as "stick electrodes," are coated with flux that releases gases and forms a protective shield around the weld pool. This coating helps to protect the molten weld metal from atmospheric contamination and improves the stability of the arc.

To choose the appropriate SMAW electrode, consider factors such as the type of base material, welding position, current type (AC or DC), and desired weld properties. Electrodes come in various classifications, such as E6010, E6011, E7018, etc., each with its own specific properties.

2. Gas Metal Arc Welding (GMAW) Electrodes:
GMAW electrodes, commonly known as "MIG" or "wire" electrodes, are consumable wires that feed through a welding gun. They are primarily used in gas metal arc welding processes, where a shielding gas (such as argon, helium, or a mix) protects the weld from atmospheric contamination.

GMAW electrodes come in different wire diameters and compositions, such as ER70S-6, ER308L, etc. The selection depends on factors like the type of base material, desired weld properties, and the required welding process (short-circuiting transfer, globular transfer, spray transfer).

3. Flux-Cored Arc Welding (FCAW) Electrodes:
FCAW electrodes, similar to GMAW electrodes, are consumable wires used in flux-cored arc welding processes. They have a hollow core filled with flux, which provides a shielding gas when melted, eliminating the need for external shielding gas.

FCAW electrodes are classified as either self-shielded or gas-shielded depending on their usage. Self-shielded electrodes (designated by "E71T") do not require external shielding gas, whereas gas-shielded electrodes (designated by "E70T") use additional shielding gas for better weld quality.

When selecting electrodes for arc welding, it is crucial to consider factors such as base material compatibility, welding process requirements, positions, desired weld properties (strength, corrosion resistance, etc.), and the specific welding technique being used. The manufacturer's recommendations and welding codes can provide further guidance on electrode selection for specific applications.