7 FUNDAMENTAL FACTORS IN ELECTRODE SELECTION FOR ELECTRIC ARC WELDING.

1.- Identify the base metal.

2.- Know the type of current available for welding, that is, whether direct or alternating current is available.

3.- Know the position in which the weld must be performed.

4.- Know the thickness and shape of the base metal.

5.- Know the joint design.

6.- Know the service specifications required for the joint.

7.-Know the efficiency and deposition rate of each electrode.

Once the electrode has been selected according to the above criteria, it is necessary to select the current (amperage) at which it will be operated according to its diameter. If the operating current is direct or continuous, the polarity recommended by the manufacturer must be used.

Even though the different types of electrodes for various applications have different operating characteristics, there are some general implicit rules that apply without exception to all types of covered electrodes.

WELDING ELECTRODES ACCORDING TO THE BASE MATERIAL TO BE WELDED

1. Carbon steels.
2. Low-alloy steels.
3. High-alloy steels.
4. Electrodes for welding stainless steels.
5. Electrodes for gouging, beveling, and piercing. (These electrodes are known as Tool Electrodes).
6. Wires for welding carbon and low-alloy steels using the SAW (Submerged Arc Welding) process.
7. Wires for welding carbon steels using the GMAW (MIG/MAG) process.
8. Electrodes for welding cast iron (gray, malleable, and nodular).
9. Electrodes for rebuilding parts subject to wear.
10. Rods for welding using the (GTAW) TIG. Argon process.
11. Rods for welding using the Oxy-fuel OFW process.
12. Non-consumable Tungsten electrode for welding using the GTAW (TIG) process.