DCEN and DCEP in welding are two important current polarities. Both play a crucial role in all types of welding activities. The polarity means the direction of the current that flows through a circuit. In the DCEN circuit, the current moves from the electrode to the workpiece. And in the DCEP circuit, the flow of current is from the workpiece to the electrode. Generally, arc welding is employed widely in the welding industry. It is a type of fusion welding process which uses an electric arc for supplying necessary heat to join the base metals and the filler metals. In this process, the conductive base plate is connected to one terminal of the power source and the electrode to another terminal. So, take a look at the various aspects of DCEN and DCEP in welding.
- What does DCEN Stand for?
- What does DCEP Mean?
- DCEP and DCEN Similarities
- DCEN and DCEP Differences
- Why does Mostly GMAW Use DCEP?
- Application of DCEP Polarity in SMAW
- Polarity Effects on Submerged Arc Welding
- Safety Measures for DCEN Welding Currents
What does DCEN Stand for?
DCEN stands for Direct Current Electrode Negative. It is a straight polarity and also called Direct Current Straight Polarity (DCSP). It takes place when an electrode is connected to the negative terminal of the power. In arc welding, the base metal is attached to one point of the power and the electrode is connected to the other terminal of the same power source. And the polarity solely decides the flow of electron between the electrode and the base metal. In arc welding, the power source provides both DC or AC power, but it depends on the connection made. And DC power can supply both straight polarity and reverse polarity.
What does DCEP Mean?
DCEP means Direct Current Electrode Positive or Direct Current Reverse Polarity. In this process, the electrode is connected to the positive terminal of the power source and the base metal to the negative terminal.
Similarities between DCEP and DCEN
The similarities between DCEP and DCEN are as follows.
- Both the polarities constitute a prime source of heat in arc welding i.e. electric arc.
- Welders can apply both DCEP and DCEN polarities for the joining of two or more components together. However, the result may be slightly different.
- In the case of AC supply, both polarities occur repeatedly one after another in every cycle.
DCEN and DCEP Differences
Despite being similarities, the differences, features in both the polarities DCEN and DCEP are as follows.
|DCEN (DCSP)||DCEP (DCRP)|
|Also called Direct Current Straight Polarity||Also, Direct Current Reverse Polarity|
|Electrode connects with the negative terminal of the power source and base metals to that of the positive terminal.||Base metals connect with the negative terminal of the power source and electrode to that of the positive terminal|
|2/3rd of total arc heat generates near the base plate and rest at the electrode tip||2/3rd of the total arc heat generates at electrode tip and rest near the base plate|
|Electrons liberate from the electrode tip and strike the base metal surface||Electrons liberate from the base metal surface and then strike the electrode tip|
|Filler metal deposition rate is quite low pertaining to consumable electrodes||Filler metal deposition rate is high due to the greater portion of arc heat generation at the tip|
|Straight polarity easily provides a proper fusion of the base metal||Incomplete fusion may occur due to less heat generation near base metal|
|Risk of inclusion defects is high if base plate surfaces are not cleaned||Rare chances of inclusion defects due to the good arc cleaning action|
|Poor oxide cleaning action by the arc||Arc provides good oxide cleaning action|
|Chances of high distortion and broader HAZ||Chances of distortion and HAZ is less|
|Suitable for with high melting temperature metals like titanium and stainless steel||Suitable for low melting temperature metals like aluminum and copper|
|Generally, not suitable for welding thin plates||With DCRP, thin plates can be welded.|
Why does Mostly GMAW Use DCEP?
DECP polarity is widely used in Gas Metal Arc Welding. The main reason is as it produces a low spatter, stable arc, good weld bead, smooth metal transfer, and deep penetration for welding currents. For gaining good results on galvanized sheets, welders can use some specific wires with chemical composition in DECP polarity and results in excellent performance.
Application of DCEP Polarity in SMAW
The DCEP or AC is used in most of the covered electrodes. In SMAW, the coated fluxes for covered electrodes make the welding process the most versatile in terms of polarity. Some of the electrodes provide good performance with DCEP or AC and DCEN.
The covered electrodes are as follows:
- E6013 (RB-26)
- E6019 (B-17)
- E7024 (ZERODE-43F)
On the other hand, high cellulose electrodes, in pipe welding, are used with DCEN polarity. They are as follows:
- E6010 (KOBE-6010)
- E7010-P1 (KOBE-7010S)
- E8010-P1 (KOBE-8010S)
Low carbon type Cr-Mo electrodes used only with DCEP-
- E7015-B2L (CMB-95)
- E8015-B3L (CMB-105)
Polarity Effects on Submerged Arc Welding
Polarity directly affects the production quality of welds. Welders should first decide which current flow they need before striking the electrode. In the SAW process, the combination of wire and flux decides the selection of polarity used. The welding process using DCEP consumes higher flux than using AC depending on the type of flux. DCEN, DCEP, and AC polarities can affect the mechanical properties of the welding. Therefore, the combination of flux and wire is crucial. Welders should use the polarity where the required quality for the metal is high.
Safety Measures for DCEN Welding Currents
The welding machine is a very powerful piece of electrical equipment. A little ignorance and mistake can cost a life. Therefore, everyone dealing with welding machines should take necessary safety precautions. The following safety tips are welders while operating the DCEN welding system.
1. Wear personal safety equipment such as gloves, helmets, and clothing. They will limit the reach of possible harmful rays to skin and eyes. Insulated gloves will help hands from electrocution.
2. Keep the working area dry and organized to prevent any risk electrocution. The working areas should not be massy. Keep only the needed and necessary equipment with you.
3. Check negative and positive terminals and make sure the torch is attached to the negative terminal and the workpiece to the positive terminal. Contrary to that, there will be messy beads, lack of control, and burning of electrode excessively.
4. Attach a workpiece clamp safely and make sure a full electrical circuit runs through the metal and back to the machine. Because the loose clamp will disrupt the path and causes shocks.
Thus, the information on DCEN and DCEP in welding provides a deep understanding of students, welders, and other professionals. Both the polarities play a crucial role in any welding process and the production of required welds.
Related: Other Welding Types