There are many types of welding rods. You should be in a position to differentiate the various types of welding rods available. Different rods have different strengths and weaknesses.
In this article, you will get to know various types of welding rods and their features.
Welding rods are available in two major categories- the consumable and non-consumable electrodes. Consumable electrodes refer to a wire joined to a welding machine. The wire melts when a current is passed through the welding machine.
On the other hand, non-consumable electrodes which do not melt.
The welding rods are usually coated since the bare rods are difficult to use. The coating materials vary widely. However, some welding rods do not have a coating. These particular type of rods are used in welding manganese steel.
To accomplish a welding job; it’s essential to choose the right welding rod. That’s why this article is crucial.
Types of consumable electrodes
1. Stick Electrodes
For these rods, the coating is made of more than one metal which is similar to the metals being joint together. The coating is a thin layer placed by brushing or spraying.
This type of rod is suitable for enhancing the stability of the arc. Usually, it’s difficult to create an arc using a bare rod. Additionally, a light coated rod is essential since it contains very few or no impurities at all. It rod is used for easy and neat welding.
2. Shielded arc Electrodes
Shielded arc electrodes are made of heavy coating. The rods are suitable in welding of cast iron since they are made of tougher material as compared to light coated rods.
Shielded arc electrodes have three coating types namely;
- Cellulose Coating. The weld zone is protected with a gas layer. This type of shielded wire is suitable for welding tasks that require strong welds. The welded area is tightly protected from gases that weaken the welds.
- Mineral coating. The coating is made of mineral substances. The welding zone is protected with a slag layer. The slag makes the weld zone cool slowly drawing the impurities to the surface causing the weld durable and robust.
- Cellulose and minerals coating.
Shielded arc electrodes have similar benefits as light coated electrodes. The rods reduce impurities and make smooth and neat welds.
Non-consumable electrodes have two types only;
1. Carbon Electrodes.
These electrodes are made using carbon graphite. The rods are used in cutting and welding. The rods can have a copper coating or bare. There are no particular specifics on the sizes. The electrodes are customized based on the job requirements.
2. Tungsten Electrodes.
The rods are suitable for light welding. The tungsten electrodes are weak, unlike its alloys. Also, the tungsten is not ideal for high current welding which is vital for tough welding. Apart from these pure tungsten electrodes which have shortcomings, there are two alloys of tungsten- zirconium, and thorium.
Zirconium electrodes can be used with alternating current.
But, the most common tungsten alloy electrodes contain thorium. The wires are believed to last longer. Unlike pure tungsten electrodes, these electrodes can be used even with high current.
Always use tungsten electrodes with the maximum current to maintain the arc. Also, use touch-starting welding machine instead of a direct current device. It’s easier to weld, and you can be in control. Finally, remember to grind the electrodes on a particular point.
Classification and Identification of Welding Rods
Different types of electrodes have codes for identification. The code has the letter ‘E’ at the start which stands for electrode. 4 or 5 digits follow this letter. The 2 or 3 digits stand for the material’s tensile strength. For instances, number 40 would mean the electrode can withstand 40,000 pounds per square inch of force.
The third digit which is 1 or 2 stands for the position where you can use the rod. A 1 means the rod can be used in all locations. A 2 means the rod can only be used on flat or horizontal positions.
The last digit signifies the type of coating used on that particular electrode. Knowing the coating type helps you identify which current type to use.
The welding rod types vary based on the material used, the rod size, their tensile strength, and the suitability of use in different positions.
Notably, consumable electrodes are smaller in diameter than the metals on which they are being used. The smallest consumable electrode is 1/16 inch in diameter. The sizes can go as high as five times in diameter.
The electrodes should have high tensile strength than the metals being joined. The tensile strength of the electrode refers to the force it can withhold. A wire with a high tensile strength can make strong and durable joints.
The electrodes contain iron powder in different percentages. The iron powder when heated forms steel. The higher the percentage of iron powder on an electrode the higher the molten metal for welding.