Welding is one of the most important processes in metal fabrication. This is why you must always be on the lookout for any welding defects that may arise. With the proper strategy, you can prevent any problems from happening. But first, you must know the causes of welding defects.
Here are the most common welding defects, their causes, and what you can do to fix them:
Spatter is a welding flaw that happens when little drops of molten material dribble on the metal. This problem is most common in gas metal arc welding or GMAW. Some of the main causes of welding spatters are high running amperage, low voltage settings, contaminated surface, incorrect polarity, or when the arc is too long.
There are a few strategies that can help you avoid spatters in the future. These include cleaning the surface before welding, reducing the length of the arc, using proper polarity, and increasing the electrode angle.
Porosity is a condition that occurs when nitrogen, oxygen, and hydrogen are absorbed in the molten welding material. This will cause solidification inside the welded metal and cause problems in the process. Porosity is caused by inadequate electrode deoxidant, using a longer arc, too much moisture, incorrect surface treatment, surface contamination, and the presence of rust, grease, or paint.
To avoid porosity you must clean the welding materials before usage, always use dry electrodes, use the correct arc length, and make sure that the gas flow meter is optimized with proper pressure and flow. Using the right electrodes and proper welding technique will also help prevent this problem.
Undercut is one of the welding defects that occur when the voltage of the arc is too high. It can also occur when the speed of the weld is too fast or if you use the wrong angle, leading to more heat on the edges. Incorrect usage of gas shielding and poor welding techniques can also be the cause of undercut.
In order to prevent this problem from happening, be mindful of the speed of the weld, use the proper angle of the electrode, reduce arc length, reduce the current when you are approaching thinner areas of the metal, and use the multi-pass technique.
This issue usually happens during the cooling and hardening part of the welding process. When the welding sequence does not fit the weld, it will lead to insufficient clamping before welding.
To prevent deformation from happening, make sure to weld both sides of the joint from the center out, going in opposite directions. You can also use a large electrode or change the sequence of the welds if you notice any sign of deformation.
Cracks are one of the most overlooked issues. They begin small and grow larger over time. If you want to fix a crack in the welding job, it will take you more than just filling the gap with material. The best way strategy is to prevent it from happening at all. The common causes of cracks are the use of hydrogen when you weld ferrous metals, contamination of the base metal, high welding speed, not preheating the equipment before welding, and a poor joint design.
In order to avoid cracks, do not rush the grinding, cleaning, and filing of the plate edges so that they will perfectly fit together. Reheat all sides of the joint, make sure that you have the right temperature, and double check if you have just the right amount of heat before welding. In order to check the heat accurately, you can test the settings of your machine.
6. Incomplete Penetration and Fusion
Incomplete fusion occurs when the weld does not fuse one side of the joint. But, when both sides are not fused, it’s called incomplete penetration. These issues occur because of low heat input, contaminated surface, incorrect electrode angle, and incorrect electrode diameter.
The best way to solve incomplete fusion and penetration is to use a wider root gap, clean the metal properly before welding, and use the correct electrode diameter for the thickness of the material you are welding. It will also help if you lower the travel speed and carefully weave in between the edges.
Knowing all the bad welds and causes is important to make sure that the welding job is strong, safe, and of high quality. For all of your general welding needs, Flawless Steel Welding provides the best steel fabrication in Colorado. We offer commercial and structural solutions such as welding, steel erection, steel fabrication, and structural steel services. If you want to know more about our services, visit our website or contact us now!