In welding, how to select an electrode is one of the keys to a successful result! And since there is a great variety of models and types of electrodes, a series of aspects must be considered when selecting it.
The electrode, is used to carry electrical current through the work piece and join two pieces together. Depending on the process, the electrode it can be consumable, in the case of metal gas welding or shielded welding, or non-consumable.
In forward polarity, the material is the positive and the electrode the negative and in opposite polarities the electrode is positive and the material is negative. With each of these configurations, different characteristics are obtained in welding.
To make an appropriate choice of electrode, a series of factors must be taken into account that, in combination, will indicate which is the most suitable electrode for the work to be carried out. We indicate these factors.
material to be welded
Each type of material has specific chemical and mechanical characteristics, according to which a type of material is required. electrode or another. We indicate below what is the electrode suitable according to the material you need to weld.
- Mild steel: commonly known as iron, this material does not require many demands to be welded. Almost all types of electrodes to work with iron. You can make use of rutile electrodes or rutile, from basic electrodes, and even with stainless steel electrodes.
- Steel with alloys: this material is a bit more special. In cases where the percentage of carbon is higher in this type of material, it usually receives heat treatments that give it hardness and rigidity. For this type of steel, it is most convenient to use at least one basic electrode or of stainless.
- Stainless steel: this type of material can only be welded with electrodes stainless steel.
- Molten materials: for this type of material, electrodes specific. You just have to request them from your provider.
It is very common to work with materials that have different thicknesses. And for a quality weld, the thickness of the material must be considered as well as the diameter of the electrode.
It is recommended to implement the ratio of thin materials with small diameter electrodes, and therefore with low current intensity.
If you work with sheets between 1mm or 2mm thick, it is best to use electrodes 1.6mm in diameter, and adjust the intensity of the welding machine very well. Likewise, it should always be spot welded, allowing the material to cool and avoiding perforating the sheets.
As for the thick thickness steels, they support practically the electrodes of any diameter, from the finest to the thickest. However, for thick steels it is advisable to weld with electrodes 2.5mm, 3.25mm or 4mm in diameter.
Stress to be supported by welding
This aspect should also be kept in mind when selecting the electrode to use. It is a highly relevant factor that should not be neglected.
In the event that the weld joints do not have to withstand great stress, they may be used. rutile electrodes (6013). These are widely used in ironwork such as the manufacture of doors, stairs, bars, etc. These materials and their welds are not subjected to compression, torsion, traction or weight stresses. That is why the rutile electrodes, which provide a soft and flexible weld, are suitable for this type of work.
For the most demanding and quality welds in the area of stress, the basic electrodes (7018) are indicated. This type of electrode Provides higher quality mechanical characteristics to solder joints.
type of welding machine
The number of models of welding machines that work with electrodes is very wide.
Each model or type of machine makes use of one or more specific types of electrodes. According to the specifications of your machine, you must select the electrode.
The machines have their power and electrode limitations, so you must validate this aspect when choosing the type of electrode to use.
The electrical power you have is an important limitation in the diameter of electrode. the diameter of the electrode largely determines the power that the welding machine will consume.
When working with a electrode thick, the power demand of the machine increases. So it is very likely that your electrical installation will trip due to excess consumption, and overheating of the electrical network will occur.
In the event that you only have 3000 watts, you should not use electrodes with a diameter greater than 2.5mm. As the concentrated power of your electrical supply decreases, you must decrease the diameter of the electrode.
Your welding skills
The electrodes behave and work differently, because each of them has technical requirements. So at the time of welding, you will encounter some difficulties if you do not use a electrode that you dominate
In the event that you are starting out in welding work, the electrodes most recommended are those of rutile. This type of electrode starts much easier, which favors beginners.
As you master the different welding techniques, you will be able to choose the basic electrodes. With this kind of electrode booting up is a bit tricky, but once you get the hang of it you’ll be able to work with them without any problems.
The mastery you have over the welding task is also an aspect to consider when choosing the electrode.
Additional aspects to choose an electrode
- You must look for a electrode that matches the composition and strength properties of the metal which will be the base. For example, if you want to weld low carbon steel (this is the one that is commonly welded), the E60 or E70 type electrode will be used.
- Next, the type of electrode suitable for the surface to be welded will be sought, for this the third number of the electrode will be set: E601.
- The electrode can be used with AC or DC.
- Analyze the design of the union and the assembly that it requires and select the electrode that provides the best penetration characteristics. For example, if working on a joint where one side is not beveled, E6013 or 11 will provide good penetration.
- For thin materials it is recommended to use an E6013 to achieve a light and smooth arc.
- To weld thick and heavy materials or with complicated joint designs, you should use a electrode of maximum ductility.
- If the environment has low or high temperature, shock waves, the best to use is a low hydrogen electrode such as the E7018, which are also known as basic electrodes.
- One more factor to consider is production. If working in flat positions, a electrode E7014 or E7024, such as contain iron powder and provide high deposition rates.
It is of great importance to consider the detailed parameters to select the welding electrode suitable. This way you will be sure to execute a neat job.