Not only does the type of welding and materials used dictate specific characteristics for welding metals together, but the electrical current has a significant impact on your results. These currents produce varying levels of power and heat generation, which will result in differences in the weld itself as well as the working process.
What does DCEN stand for in welding? DCEN stands for direct current electrode negative, where the electrode is attached to the negative terminal for power, and your metal is connected to the positive terminal. This results in more heat being placed on the work metal and less on the electrode, which is best used on thinner metals.
Using DCEN as opposed to DCEP (where the electrode is attached to the positive terminal and electricity goes through the welding rod) will depend on the metal you are working with and desired results. There are specific welding practices that work better with DCEN than alternatives, making the electrical current choice essential for clean and effective welds.
How Does Direct Current Electrode Negative (DCEN) Work?
When using a DCEN setup, also known as straight polarity, the electrons that generate heat and energy flow from negative to positive. Your welding torch should be hooked up to the negative terminal on the welding machine, and the workpiece clamp is attached to the workpiece and positive terminal.
This means that the electrons are traveling from the welding electrode to the workpiece, which results in a greater distribution of heat being placed on the metal. Around 2/3 of the heat generated during this process will be transferred to the piece of metal while the other 1/3 heats the electrode. This impacts the amount of penetration the electrode will have.
When less heat is generated by the electrode on the welding torch, the penetration is not as powerful, which is best for thinner metals that do not require excessive heat to melt the needed areas. This process is the opposite of DCEP (where the electrons flow from positive to negative).
DCEN polarity configurations have two primary impacts on your weld, and this welding method is often chosen for these reasons:
- Penetration levels: While you can reduce the penetration level because there is less heat being generated by the electrode itself, the increased heat on the metal piece can allow for deeper penetration than DCEP and other welding current methods. This is particularly true in GTAW (gas tungsten arc welding) when you can apply more heat.
- Higher burn-off rate: The burn-off rate describes the amount of consumable electrode or wire that is melted into the weld pool. Because more heat is placed on the workpiece, the consumable will burn faster.
The type of welding method and material you use will largely dictate the choice of polarity. Clean and sturdy welds are the goal, and the electrical current type you use can influence that greatly.
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The Difference Between DCEN and DCEP >> Check out the video below
What Types of Welding Use DCEN?
It is crucial to make sure that the type of welding you do will be compatible with the electrical current that is chosen. These currents impact the quality of welds and the energy output onto the metal workpiece itself.
Three primary types of welding are compatible with DCEN currents, and they are:
- Tungsten Inert Gas welding (TIG)
- Shielded Metal Arc welding – Root or overlay (SMAW)
- Plasma Arc Welding
The most common application of DCEN is with Tungsten Inert Gas (TIG) welding (also known as GTAW). A tungsten electrode is negatively charged to prevent it from overheating. This puts 2/3 of the heat onto the metal itself.
You should also consider using DCEN for flux-core electrodes because it prevents melting and excessive heat on the electrode. This is used in shielded metal arc welding (SMAW) with the use of a consumable electrode. Also known as stick welding, it can also be used with a DCEP current for general welding applications.
The DCEN process should also be used for plasma arc welding for similar reasons, to keep the heat on the workpiece, as opposed to the electrode. When completing any of these types of welding, you should be looking for specific electrodes that are compatible with DC (as opposed to AC) currents. This will be stated on the box itself.
Beyond the type of welding process, DCEN will be more compatible with certain types of metal. As a general rule, most metals are compatible, including steels, stainless steels, and titanium. You should NOT use DCEN on aluminum or magnesium as they have an oxide coating on them that will not result in competent welds (you can remove this coating if needed).
One of the most common applications for DCEN systems is on thin pieces of sheet metal. Lower levels of penetration are easy to control, and the arc produced is typically narrower for cleaner results. It is not recommended to use DCEN for MIG, GMAW, and SAW welding use.
Related reading: 9 Different Types of Welding Processes & Their Advantages
How to Safely Use DCEN Welding Currents
Because you are working with a very powerful piece of electrical equipment, it is essential to take necessary safety precautions. The following tips will help to prevent the dangers associated with DCEN welding. The primary dangers include electric shocks, burns, and eye damage associated with light exposure.
The following safety measures must be taken to ensure that you weld safely with a DCEN system:
- Check torch and clamp polarity: Look at the welding machine itself as it will have plugs for both negative and positive terminals. Make sure that the torch is securely fastening into the negative terminal (may also say ‘straight’ for straight polarity) and the workpiece clamp is plugged into the positive. Switching them will result in reduced control, messy beads, and excessive electrode burning.
- Safely attach workpiece clamp: The ground is used to make sure there is a full electrical circuit that runs through the metal and back to the machine. Make sure the clamp is securely fastened and will not be in the way to bump into easily. Disrupting this path could lead to shock.
- Wear personal protective equipment: Make sure you are always wearing protective helmets, gloves, and clothing to limit potential contact with bare skin. Insulated gloves will help to prevent risks of electrocution.
- Keep work area organized and dry: Your work area should be free of clutter and only include your needed equipment and materials to prevent accidents. This area must also be dry to avoid electrocution, especially on the metal workpiece, welding machine, and your body.
Being extremely careful and taking additional steps to remain safe while using the machine will create good habits for safe use. Compared to an alternating current (AC) that is also used in welding, DC systems tend to be much more stable and controlled, resulting in fewer accidents when proper safety measures are taken.
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Using DCEN in Welding
Direct current electrode negative (DCEN) can be easily configured with the proper applications to the negative (torch) and positive (metal workpiece) terminals. The welding machines should label these terminals very clearly to make it easy to set up the cables correctly. Ensure that there are no barriers between the cables and the workpiece for optimal safety.
DCEN is a very effective method for TIG, flux-cored, and plasma arc welding applications. It can be used on a wide variety of metals and works best for most projects that use thinner metals! Make sure you take necessary precautions to ensure that the work can be done safely and produce clean results. By following proper welding practices, you will make beautiful, durable welds every time!
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