Overhead arc welding is a challenging but rewarding technique that allows you to weld joints in the overhead position. This means that you are working against gravity, which can cause the molten metal to sag or drop. To overcome this difficulty, you need to use the right equipment, settings, and skills. In this article, we will explain the basics of overhead arc welding and give you some tips and tricks to improve your results.
I. What is Overhead Arc Welding?
Overhead arc welding is a type of arc welding that involves welding a joint in the overhead position. Arc welding is a process that uses an electric arc to heat and melt the base metal and the filler metal (usually a consumable electrode) to create a weld pool. The weld pool then solidifies to form a strong bond between the metal pieces.
Overhead arc welding can be done with different types of arc welding processes, such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW), flux-cored arc welding (FCAW), and gas tungsten arc welding (GTAW). Each of these processes has its own advantages and disadvantages, depending on the application, material, and desired outcome.
II. Why Use Overhead Arc Welding?
Overhead arc welding is often used when the joint cannot be moved or rotated to a more comfortable position, such as flat or horizontal. This can happen when welding pipes, tanks, ceilings, bridges, or other structures that require overhead access. Overhead arc welding can also be used to create complex shapes or patterns that are not possible in other positions.
Overhead arc welding has some benefits over other positions, such as:
It can produce stronger and more uniform welds, as the molten metal is less likely to flow out of the joint or create gaps or porosity.
It can reduce distortion and shrinkage, as the heat is evenly distributed across the joint and the metal cools faster.
It can save time and money, as it eliminates the need for scaffolding, cranes, or other equipment to move or support the workpiece.
III. How to Do Overhead Arc Welding?
To do overhead arc welding successfully, you need to follow some basic steps:
Choose the right equipment and settings. You need to select the appropriate arc welding process, power source, electrode, shielding gas (if applicable), and personal protective equipment (PPE) for your project. You also need to adjust the amperage, voltage, wire feed speed, travel speed, and electrode angle according to the material thickness, joint type, and position.
Prepare the workpiece and the joint. You need to clean the metal surface from any dirt, rust, oil, paint, or other contaminants that can affect the quality of the weld. You also need to align and clamp the metal pieces properly and create a suitable gap or groove for the filler metal.
Position yourself comfortably and safely. You need to find a stable and ergonomic posture that allows you to see and control the weld pool clearly. You also need to wear appropriate PPE, such as a helmet, gloves, jacket, boots, and respirator (if needed), to protect yourself from sparks, spatter, fumes, radiation, and electric shock.
Strike the arc and start welding. You need to strike the arc by touching the electrode tip to the base metal and then quickly pulling it away. You then need to move the electrode along the joint at a steady pace, keeping a short and consistent arc length. You also need to weave the electrode side-to-side slightly to fill the joint evenly and prevent sagging or dropping of the molten metal.
Inspect and clean the weld. After finishing the weld, you need to inspect it for any defects or irregularities, such as cracks, holes, undercutting, slag inclusion, or lack of fusion. You also need to remove any excess metal or slag from the weld surface using a chipping hammer, wire brush, grinder, or other tools.
IV. Tips and Tricks for Overhead Arc Welding
Here are some tips and tricks that can help you improve your overhead arc welding skills:
Use a smaller diameter electrode or wire than you would use in other positions. This will reduce the amount of filler metal and heat input and make it easier to control the weld pool.
Use a lower amperage setting than you would use in other positions. This will prevent overheating and burning through the base metal and filler metal.
Use a drag or pull technique rather than a push technique when moving the electrode along the joint. This will help you maintain a better view of the weld pool and avoid spatter or slag falling on your face.
Use a fast-freeze electrode or wire that solidifies quickly after leaving the arc. This will prevent the sagging or dropping of the molten metal and create a smoother and flatter weld bead.
Use a backing strip or bar behind the joint if possible. This will support the molten metal and prevent burn-through or excessive penetration of the base metal.
Practice on scrap metal or test coupons before welding on the actual workpiece. This will help you familiarize yourself with the equipment, settings, and technique and improve your confidence and accuracy.
V. Conclusion
Overhead arc welding is a useful but challenging technique that requires proper equipment, settings, and skills. By following the steps and tips outlined in this article, you can master overhead arc welding and create strong and durable welds in any position.
If you want to learn more about overhead arc welding, you can check out these resources:
