Welding electrodes are wire lengths attached to your welding equipment in order to generate an electric arc. An arc is created when current travels over this wire, which creates a lot of heat in order to melt and fuse metal for welding. Today we are going describe how to manufacture welding electrodes via step by step process. However, there are a number of welding electrode manufacturer to get a ready made one.
A coated metal wire serves as an electrode. It’s constructed of comparable materials as the metal that’s being welded. There are two types of electrodes: consumable and non-consumable. Electrodes are consumable in shield metal arc welding (SMAW), also known as stick welding. This implies that the electrode is consumed during use and melts with the weld.
Electrodes used in Tungsten Inert Gas welding (TIG) are non-consumable, which means they do not melt and form part of the weld. Electrodes are continually supplied wire during GMAW or MIG welding. Flux-cored arc welding necessitates the use of a flux-filled, constantly fed consumable tubular electrode.
Welding Electrodes: The Different Types
In general, there are two types of welding electrodes, depending on the process:
1. Consumable Electrodes
The melting point of consumable electrodes is low. In Metal Inert Gas (MIG) welding, certain types of welding electrodes are preferred. Materials like mild steel and nickel steel are utilized to make consumable electrodes.
Consumable electrodes must be replaced at regular intervals, which is the only precaution you must take. The sole drawback of employing such electrodes is that they don’t have a wide range of industrial uses, but they are simple to use and maintain.
Consumable electrodes are classified as follows:
- Bare Electrodes
Bare electrodes are electrodes that do not have any form of coating and are typically utilized in circumstances where a coated electrode is not required.
- Coated Electrodes
The coating factor is used to classify coated electrodes. The coating factor is the ratio of the electrode diameter to the core wire diameter.
The subtypes of coated electrodes are as follows:
Electrodes with a coating factor of 1.25 and a light coating. Impurities like as oxides and phosphorous can be removed from electrodes using a light coating. Arc stability is also improved by light coating.
Coating factor of 1.45 on medium coated electrodes.
Electrodes that are shielded arc or heavily coated, with a coating factor ranging from 1.6 to 2.2. The composition of these electrodes is correct and well characterized. Electrodes with cellulose coating, electrodes with mineral coating, and electrodes with both cellulose and mineral coating are the three varieties of extensively coated electrodes available.
2. Non-Consumable Electrodes
Refractory electrodes are another name for these sorts of welding electrodes. Non-consumable electrodes are divided into two categories:
Carbon or graphite electrodes are made out of carbon and graphite and are commonly used in cutting and arc welding applications.
Tungsten electrodes: Tungsten electrodes are non-filler metal electrodes that are made entirely of tungsten.
As the name implies, these welding electrodes are not consumed during the welding process, or to put it another way, they do not melt during welding. However, the length of the electrode is reduced in practice owing to the vaporization and oxidation processes that occur during welding. Because non-consumable electrodes have a high melting point, they cannot cover the gap in the workpiece.
Non-consumable electrodes are constructed of pure tungsten, graphite, or carbon with a copper coating. Carbon has a melting temperature of 3350 degrees Celsius, while tungsten has a melting point of 3422 degrees Celsius. Tungsten inert gas welding (TIG) and carbon arc welding both employ non-consumable electrodes.
Making the Electrodes – Step-by-Step Guide
The wire begins as a strewn-together coil of metal wire. Stainless steel wire is commonly used, however the type of wire used depends on the electrode being created. Heat treatment of the wire can improve its ductility. The wire is then pulled through drawing dies and shaped until it is consistent and totally straight at a predetermined diameter on a metal forming machine.
Cutting the wire
Metal rollers lead the straight metal wire into a cutting apparatus, which slices it into equal segments. The length of these segments varies depending on the type of electrode being manufactured, although they are normally around 12 inches long. These identical wire sections will shortly constitute the electrode’s core.
Coating the surface
The metal wire must next be coated with a dry combination of components that will function as a flux. Nickel, manganese, iron, aluminum, titanium dioxide, mica, and limestone can all be found in the mix. To aid distinguish between different types of electrodes, a coloring agent will be applied. After that, potassium silicate is added to moisten the mixture and function as a bonding agent.
Applying the coating
A hydraulic extrusion press is manually loaded with the wet mixture. To create briquettes, 120 tonnes of pressure will be applied. The wires are then passed through rollers into the extrusion press and coated with the flux mixture. The wires pass through one at a time, but at a breakneck speed of up to 1000 per minute.
Cleaning and sanding the electrodes
The wire is entirely coated as it emerges, but it must be sanded before it can be utilized. The lowest few inches of flux are sanded away to reveal bare wire that may be grabbed, and the tip is bevelled to aid in the creation of an arc.
Examining the electrodes
Workers will inspect electrodes manually to verify that the coating is uniform and that they seem as they should. Electrodes that fail manual review will have their flux extracted, and the wire will be reinserted into the machine to attempt again.
Heating the electrodes
After the electrodes have been tested for quality, they are placed in an oven to dry off. The goal is to decrease moisture content to no more than 4%, which can take up to 5 hours at temperatures above 900 degrees Fahrenheit.
After the electrodes have cooled, they are run through a printing machine, where the welding rod number and model, as well as a colored strip to identify the electrode type, are printed.