There are lots of methods being used by the welders for combining two pieces of metals. The type of tools, heat, and pressure being used in each process makes it unique.
The said welding method should be done by professionals who know how to do it. When performed properly, it can create top-notch welds.
So, if you want to know more about it, then keep on reading!
- 1 What is Polarity in Welding?
- 2 Different Types of Welding Polarity
- 3 Polarity Settings On Machines
- 4 What is a Suitable Polarity for MIG Welding?
- 5 What is the Suitable Polarity for Stick Welding?
- 6 What Polarity is Suitable for TIG Welding?
- 7 Conclusion
What is Polarity in Welding?
Polarity is having two different poles where the negative particles of the electric current run from the negative pole to the positive one. A positive pole is an area where there is less negative charge than the one in the negative pole. With polarity settings in welding, you can select where each pole is located and if they change. Any of the poles can exist either on the side of the electrode or on the side of the welding area. In DC, the poles don’t change and electricity runs from negative to positive (e.g. only from the electrode to the piece or only from the piece to the electrode). In AC the poles change at a specific frequency and therefore the electricity particles oscillate back and forth. The weld properties are completely different from each type of electric current.
In school, you might remember yourself assuming in exercises that electricity runs from the positive pole to the negative one because of a false misconception before the invention of microscopes more than a century ago. The real direction of the current wasn’t important in high-school while in welding it is very important. So, because it is extremely easy to mix things up always try to figure out where the negative pole is. It’s the only way to know for sure what is happening.
Different Types of Welding Polarity
To perform TIG Welding, you need to use a power supply. This will enable you to make an arc between the two materials. The first material is designed to be welded, and the other one should be a type of electrode. As mentioned, this is a welding process known by many since it can be used in different types of metals.
The TIG Welding Polarity comes with two different types. The DC and AC TIG Welding Polarities. Both of them come with respective subtypes; the electronegative DCEN and the Electropositive DCEP. In this section, we are going to further discuss you with the different types of TIG Welding Polarity.
So, without further ado, let’s get started!
There are two AWS (American Welding Society) classifications for the SMAW (Shielded Metal Arc Welding) electrodes. These are the E6011 and the E6010. Both of them have similar properties. These two are considered to be a mild steel type of electrode. It can also be used for several welding applications. Aside from that, both of them have the same mechanical properties and operating characteristics.
But, in spite of their similarities, they still have notable differences. You can use the E6011 with both the Direct Current and the Alternating Current. On the other hand, the E6010 can be used with the Direct Current only.
Aside from that, the E6011 comes with a higher level of cellulose potassium type coating while the E6011 is high with cellulose sodium type coating.
DC Welding Polarity
The first type of Welding polarity is the Direct Current, and it’s what most welders prefer in welding polarity compared with AC. You can operate both the E6010 and E6011 electrodes with this polarity. When it comes to more serious welding applications, which include low alloy steels and pipe welding that needs higher strength, you can rely on this type of polarity.
In addition to that, it is important to keep in mind that only the E6010 electrode is capable of this kind of welding application using the DC polarity. Take note that DC+ polarity is being used for stick welding. This is because it is known for creating an excellent bead profile. Not only that, but it will also provide you with a high penetration level.
On the other hand, the DC- polarity might give you a high melt-off rate of the electrode and lower penetration. But this is the DC polarity used for welding thinner metal to avoid burn-through.
AC Welding Polarity
If the power source you are using emits an alternating current or AC, then you can expect that the reverse polarity and the straight polarity will appear. During the half-cycle, you can expect that the electrode is in the negative form. This only means that it has positive base plates. On the other half, you can now have a positive electrode and a negative base plate. Keep in mind that the frequency of the power supply will always affect the number of cycles.
Polarity Settings On Machines
Direct Current Electrode Negative Polarity (DCEN)
When you have the positive base plates while your electrode is linked to the negative source, then it is known to be a straight polarity or the Direct Current Electrode Negative (DCEN) Polarity. This is a polarity that will enable the electrons to flow to the base plates coming from the electrode.
As a result, the base plate can create more heat compared with the electrode. This only means that the electrodes have a reduced metal deposition rate. Take note that the problems resulted from not enough fusion will be removed.
This type of polarity does not have a cleaning action feature. This only means that defects might occur when the base plates are not properly cleaned before using it.
Advantages of DCEN
DCEN will provide you with enough amount of base metal fusion. As a result, the metal can get proper penetration. Aside from that, there is also less chance for low reinforcement and tungsten inclusion. This is the proper welding polarity if you are going to weld stainless steel and other high melting point metals. You can also use it to join thicker plates.
Disadvantages of DCEN
As we have mentioned, the DCEN does not feature a cleaning action. This only means that inclusion defects have a higher chance of appearing. Aside from that, it also comes with higher residual stress generation and a high level of distortion.
This type of welding polarity also comes with a broader heat-affected area. This might result in a lower level of productivity since it has a lower rate of deposition. Aside from that, we do not recommend this welding polarity in joining two thinner plates.
Direct Current Electrode Positive Polarity (DCEP)
DCEP is also known as the Reverse Polarity. It is a type of welding polarity that has a direct current of power supply, a positive electrode, and a negative base plate. Through the outer circuit, the electrons will flow to the electrode coming from its base plates. The electron will flow in the tiny passages continuously. This will enable you to create an arc.
The base plates produce electrons. These electrons will be accelerated because of the possible difference. The accelerated electrons will then produce a higher level of velocity and start hitting the electrode. This will result in the electrons to produce kinetic energy that will be later on turned into thermal energy. This will result in the electrode tip to heat up.
Many professional welders believe that an approximate measurement of two-thirds of the whole arc heat is produced at the electrodes, and the remaining parts are made at the base plates. As a result, the electrode will start to liquidize fast. Aside from that, the consumable electrodes deposition rate will also get improved.
It is worth noting that the base plates in this welding polarity do not fuse rightly. This is because they don’t have enough amount of heat. Lack of enough heat can cause different welding problems, such as high reinforcement and low penetration levels.
But take note that electrons also produce a stream that will remove the oil on the base plate. The stream will also cover the dust particles and the oxide layers you can see on the base plates’ surface. This is the process known as the oxide cleaning action.
Advantages of DCEP
As you can notice, the DCEP comes with an arc cleaning action that the DCEN does not have. When the arc is appropriately cleaned, there is a low chance of having inclusion problems. It also comes with a higher level of deposition volume. This only means that you can perform the overall welding process quickly and easily.
Aside from that, it can also decrease the complete cutting, residual stress, and distortion. This means that you can make thinly cut welding plates smoothly. This type of welding polarity is good for welding copper and other metals that have a low level of melting point.
Disadvantages of DCEP
Some of you don’t know that non-consumable electrodes have a shorter life. Also, it comes with a higher reinforcement level if the welder does not adjust the speed properly.
Since it has a low level of penetration and does not have enough melting, this welding polarity is not suitable for joining the thicker metals or plates that come with a higher level of melting points.
What is a Suitable Polarity for MIG Welding?
MIG welding is the most basic type of welding process, which is suitable for starters. This type of welding method requires the DCEP or the Direct Current Electrode Positive polarity. Welders who are using this welding method prefer using the direct current electrode positive or the direct current electrode negative.
If you are not using any gas in MIG welding, I would advise you to use DCEN. AC can be used in MIG welding and you can use it to weld aluminum or magnetized materials. However, keep in mind that there will be more spatter and inferior surface quality when using AC.
It is important to read and understand the instructions written in manuals.
What is the Suitable Polarity for Stick Welding?
As we have mentioned earlier, the expert welders use the DC+ polarity when they are performing the stick welding method. This is because it will enable you to create a bead profile and give you a higher penetration level. We don’t recommend using DC-polarity. This is because it has a higher electrode melt-off rate and lesser penetration. You can use this polarity for fusing thinner sheet metals. This is good for preventing burn-through.
What Polarity is Suitable for TIG Welding?
What is TIG Welding?
TIG welding is also known as the gas tungsten arc welding. Way back in the 1930s to 1940s, it is being used by the aircraft manufacturers to joining the magnesium-made materials. Generally, the process of making this welding goes like this: The expert will create an arc that is located between the non-consumable tungsten electrode and base metal. The first item is an electrode type that cannot be melted. A melted weld pool will be created when the arc hit the base metal.
At the weld pool, a thin filler metal will be handfed into it slowly. After that, the thin wire will start to melt. For the entire process, the inert shielding will be the wall that will protect both the weld pool and the tungsten electrode against the oxygen contamination. You should not use fluxes. After the whole process, you can now have a slag-free and sound weld that comes with the corrosion resistance property coming from the two used metals.
The aerospace industry uses this welding method in creating their airplanes and spacecraft. The fact that it has an anti-corrosive property, it is also being used by the auto companies. Auto body repair shops also start using TIG welding. Many welders are amazed by the results being given by this technique to their sculpture welding.
TIG Welding Polarity
When it comes to the TIG Welding polarity, it has a straight polarity, which is also called by some as the DC electrode negative (DCEN). This welding process is using a negative torch that has a positive work. This is a welding process that is being used for joining different types of metals. In connection with that, most of the industries are using this welding process.
When using the most popular welding method, which is TIG welding, it is important for you to use the right type of welding polarity. When performing TIG welding, we recommend you to use the DCEN or the Direct Current electrode negative polarity. The older welders also call this as the straight polarity.
For TIG Welding, the negative torch is perfect for you to prevent unnecessary tungsten overheating.
When it says “straight polarity”, it is understandable that it has negative electrode and positive base plates. When it says “reverse polarity”, it is understandable that it has negative base plates and positive electrodes. Take note that the reverse polarity will provide you with an increased deposition rate whole; the straight polarity offers a high level of penetration. By using a good welder you will learn how to use these settings a lot quicker.
Since there are lots of materials used by many welders for welding, either of the said polarities is perfect to use. If you are a beginner in this field, we recommend you to use MIG welding. But, if you are dealing with a wide selection of metal types, TIG welding is the most recommended process.
Don’t hesitate to learn more about welding on other articles of our site.