MIG welding is an arc welding process used in sheet metal fabrication for construction and repair works. From car panels and exhaust systems to shipbuilding and marine structures, the use of MIG welding is endless. This technique is beginner-friendly and easy to use. Additionally, MIG welding is fast and suitable for large-scale projects. However, there are some common mistakes many welders make that lead to defective parts and equipment damage.
Before using MIG welding, it is important to understand the common mistakes and their causes. This article explains what MIG welding is, the common MIG welding errors, and how to avoid them.
Overview of the MIG Welding Process
Metal Inert Gas (MIG) welding is an advanced technique that creates durable, high-quality welds. It uses a wire electrode that is continuously fed into the weld pool to join two metal pieces precisely. The result is a clean joint that may not need further processing. The process of MIG welding begins with proper workpiece preparation. This involves cleaning the workpiece using alkaline or neutral agents to remove all contaminants.
After that, set up the MIG welder and adjust parameters such as voltage, wire feed speed and voltage. When everything is ready, pull the trigger on the gun and touch the workpiece with it to initiate the arc. The electric arc melts the wire electrode and base metal to form a weld pool. This action melts the workpieces, and they fuse after cooling and solidification.
During MIG welding, the shielding gas, usually pure argon protects the weld pool from oxidation and contamination. MIG welding is fast and suitable for beginners because of its simplicity. This process is versatile and compatible with many engineering materials, including aluminum, steel, and copper.
8 Common Mistakes in MIG Welding and How to Avoid Them
When MIG welding, one can encounter common mistakes, especially if one does not follow proper practices. The mistakes can lead to detrimental effects and jeopardize safety. Below is an extensive discussion of eight common MIG welding mistakes and how to avoid them.
#1- Incorrect Wire Feed Speed
It is common for operators to set the wire feed speed too high or too low when welding metal pieces. High wire feed speed can lead to excessive spatter and burn-through. Conversely, a lower-than-required speed will cause incomplete fusion and weak welds. For these reasons, one must use the right feed speed for adequate penetration and consistent weld bead.
Solutions
- Make test welds to determine the correct wire feed speed.
- Follow the manufacturer’s instructions and adjust the speed based on the workpiece material and thickness.
#2- Poor Shielding Gas Coverage
Another MIG welding problem is poor shielding gas coverage. It can happen when there is an inadequate gas flow rate from the setting or leaks in the gas hose. This also occurs when wind and external factors blow away the shielding gas. Poor shielding gas coverage leads to pores in the weld, which weakens the joint over time.
Solutions
- Use proper gas flow rates based on the current and feed speed.
- When welding in windy conditions, use suitable barriers.
#3- Improper Welding Technique
There are some things you should avoid during welding to get professional results. Improper welding happens when using an incorrect travel speed along the joint. It is also a result of inadequate gun angle and distance to the workpiece. All these lead to weak welds, distortion, and undercutting.
Solutions
- Maintain a 15-20 degree gun angle.
- The distance between the gun and the workpiece should be approximately half an inch.
#4- Using the Wrong Wire Electrode
Mistakes can arise if you use the wrong wire electrode in MIG welding. The wire electrode plays a crucial role because it conducts electric current from the power source to the arc. The use of an incorrect wire electrode extends beyond incompatibility with the base metal. Using the wrong diameter is also an issue. The major consequences of electrode mismatch include cracking and poor fusion.
Solutions
- Check material specifications and select a matching filler wire.
- Use thin wire electrodes for thin workpieces and vice versa.
#5- Inadequate Cleaning of Base Metal
Another common MIG welding problem is insufficient cleaning of the base metal. Contaminants such as oil, rust, and dirt can lead to holes in the final weld and affect structural integrity. Additionally, it prevents the wire electrode from fusing completely with the workpiece. Contaminated welds are prone to cracking and discoloration.
Solutions
- Clean the workpiece and remove rust using a solvent or wire brush.
- Weld in a neat and controlled environment.
#6- Lack of Proper Ventilation
It is possible to also make the mistake of welding in a confined space without adequate air circulation. The consequences of lack of proper ventilation can be detrimental as the MIG welding process releases harmful fumes and gases. Inhaling these substances leads to respiratory problems and cancer. Additionally, poor ventilation causes discomfort and increases the risk of explosion.
Solutions
- Use fume extraction systems when welding in enclosed areas.
- Ensure cross ventilation and monitor air quality.
#7- Overheating the Weld Area
When MIG welding, one may be tempted to increase the heat settings to speed up the process. Overheating also happens when performing multiple weld passes without allowing sufficient cooling time. All these can lead to material warping and distortion. You can also experience burn through, poor weld aesthetics and degradation of metal properties.
Solutions
- Adjust heat input and match the amperage settings with the material type.
- Maintain proper travel speed and let the workpiece cool naturally between passes.
#8- Ignoring Safety Precautions
There are some important safety precautions one often overlook and ignore when welding metal pieces. These include not wearing personal protective equipment like aprons, helmets, and gloves. Welding safety also covers inspecting tools and equipment. Ignoring safety precautions can lead to burns, injuries, eye damage and electric shock
Solutions
- Organize the workspace and inspect equipment regularly.
- Wear proper PPE and ensure they are in good condition.
Conclusion
MIG welding is a popular process in modern manufacturing. It is used in many construction industries, such as aerospace, marine, and architecture, because of its ease of use and speed. However, some common metal welding mistakes beginners make can lead to serious consequences. Some of these mistakes include using incorrect wire feed speed, working in a confined environment, and inadequate cleaning of the base metal. One must avoid all these to reduce the risk of defects and produce strong welds.
