Types of electrodes: classification, labeling and features
The scope of electrical welding works is regularly updated with new methods and technologies for performing operations. However, there are basic approaches to the organization of the process. These include the use of an electrode. It is designed for convenient supply of current to the target workpiece with subsequent thermal effects. There are different types of electrodes that differ in working qualities, technical parameters, material of manufacture and purpose. But first, it’s worth finding out what a similar device is.
Products are made in the form of a rod, the base of which can be both a metal and a non-metal rigid rod. In the production it is also called welding wire. It can have a length of 25 to 45 cm and an average thickness of 2-3 cm. Actually, the rod most often acts as a carrier tool for a functional coating, through which the working process is carried out.At a basic level, there are types of welding electrodes for resistance to thermal effects - melting and non-melting. Moreover, the products of the first group may not have a coating at all. This is a bare metal wire that can be used in special environments with a protective gas supply. Coated models also have a small “clean” area for fixing in the electrode holder.
Non-metallic models include all non-consumable devices for applying current to the surface being welded. This is a narrow segment, which is based on graphite and carbon electrodes. Metallic non-consumable products are presented tungsten, thoriated and lantanymirovannymi models.
The widest group in the general class of such devices is formed by metal melting types of electrodes for manual arc welding in different conditions. For such purposes, steel, copper, cast iron and bronze elements are used. Each material has its own characteristics in terms of resistance to heat, quality of weld formation, protection from external influences, etc.Depending on the parameters of the working environment, one or another type of rod is selected.
Operational features of metal electrodes
A wide group of consumables of this type are alloy models. They are distinguished by their tendency to ignite, but at the same time they ensure the stability of arc burning. The final seam turns out reliable and durable. This option is recommended for beginners due to operational stability.
Many features and high-alloy products. In contrast to the previous category, they are characterized by resistance to thermal effects. Therefore, they are used in work with heat-resistant and cast billets. Welders appreciate the possibility of hindering the formation of cracks due to the hydrogen contained in the target material. There are special brands of filler iron, which is usually used in welding automotive parts.
Feed Direction Classification
The tactics of physical impact on the workpiece may be different depending on the conditions of work. In particular, the direction angle is of great importance from the point of view of an effective melt and the subsequent formation of a clean, strong weld.
The most popular types of electrodes for manual welding are consumables that allow you to perform operations in all positions (universal) and in the upward direction. Less commonly used tactics vertical feed from the top to the bottom zone.
Also, in some areas, special models of electrodes are used for “in the boat” welding. They allow you to effectively carry out working actions in the lower position when creating the corner joints. If the conditions do not allow the use of such tactics, then universal consumables will be used with some corrections on the mechanics of the seam. In particular, more intensive welding of the root node in the area of the junction with point melting edges will be required.
Types of electrode coatings
To date, used rutile, mineralic acid and calcium fluoride consumables to supply welding current. They differ in the features of the electrical processes, which leads to different degrees of their value for welding of a particular design. For example, rutile coatings are based on titanium dioxide with silica, magnesium, and calcium additives.In some ways, this is a universal budget solution that is suitable for all popular reconciliation methods.
Also, the electrodes with the main type of coating from ore-acid components contain silica, but in addition to it the structure is formed by manganese and iron. Such models are also widely used, and in the presence of organic elements, they manifest themselves from the best side when welding in gas-shielded environments.
Fluorite-calcium based coatings, in addition to magnesium and calcium, contain ferroalloys and fluorspar. These are specialized electrodes suitable for special working conditions.
Types of coatings by functional orientation
It is worth noting the classification of electrodes according to the tasks of welding, which they solve. Since the active part in terms of functional impact is the coating, then this characteristic will depend on it. What does it represent?
Mainly used are protective and stabilizing coatings of electrodes, which differ in structure and performance. In the first case, it may be a combination of mechanical particles collected from different materials. It turns out a hybrid mixture deposited on the welding wire.Its main task is to create a barrier to air flow.
Some protective coatings also contribute to the refinement and alloying of the metal joint. Elements of stabilizing models are designed for ionization of the welding arc. They control the combustion process, keeping it in the desired parameters.
Electrodes with magnetic coatings, which are sprayed with active powders directly during the melt, are also popular. Consumables in this category are usually used in automatic or semi-automatic welding.
Marking electrode consumables
Each classification provides its own designation of the type of electrode. Thus, the method of direction of supply is marked with numbers from 1 to 4: respectively, from universal consumables to products used according to the “boat” method. The lettering is used to indicate the thickness of the welding wire and the type of coating. For example, acid sprays are designated as A, the main ones are B, and rutile ones are R. The marking of electrode types in the thickness of the coating can be represented as follows:
- Thin layer - M.
- Average thickness - C.
- Thick coatings - D.
- Ultra Thick Models - G.
On the market, each electrode is presented with a full marking of characteristics, as well as an indication of the size and purpose.
Cost of welding electrodes
Products are delivered in packs, which vary in weight - on average from 1 to 5 kg. The cheapest offers are available for 150-200 rubles. These are kilogram packages containing universal consumables models.
What types of electrodes are the most expensive? These are carbon products intended for inverters. They are used in complex operations to perform high-quality seams on critical structures. The cost of such equipment is 1000-1500 rubles.
How to choose the electrodes?
In the selection process, filtering should begin with dimensional parameters, the main one being the diameter. The more extensive the work activities are planned, the thicker the rod should be and its coverage. For example, the processing of wide walls of a structure can be done in several approaches with thin electrodes, but the process of reorganization during the change of equipment will take a lot of time, not to mention the risks of obtaining an uneven seam.
And on the contrary, operations with corners or profile elements require not so much a long-term impact on the material, as more convenient mechanics of feeding the active element. For such purposes, universal types of arc welding electrodes with a coating thickness of 0.5 to 2 mm may be suitable.
Do not ignore the appearance of consumables, despite the instructions in the marking. High-quality electrode initially has a dry and dense surface. If there are swellings with surges and translucent pores, then the purchase should be abandoned.
The exception may be only small irregularities and longitudinal cracks. As for marking, in addition to the above parameters can be specified data on the flow. It should be understood that this value is conditional, since the material of the target blank can be different, respectively, and the number of spent items varies.
With all the differences between the electrodes, all of them can provide the expected result only if they are properly operated, taking into account the nuances of a particular process. The quality of the work of such consumables may also be affected by the basic welding equipment and accessories.And this is not to mention the characteristics of gas environments.
In working with critical structures, stabilizing types of electrodes are often used, which just minimize the influence of negative factors. High-performance alloyed and carbon models are good in conditions when it is required to ensure sealing against the background of metal resistivity. These are technologically complex operations to which only professional welders are allowed.