In the field of steel structure welding, robotic welding stations have become key equipment for improving efficiency and quality. However, spatter has always been a major challenge affecting welding quality. Weld spatter not only reduces welding quality and efficiency, but also affects the welding environment and safety, and can even damage welding equipment and the workpiece surface. Several approaches can be taken to address this problem.
First, optimize welding parameters. Excessive or insufficient welding current in the welding station can lead to unstable droplet transfer and spatter. If the current is too high, the droplet will explode due to overheating, causing spatter; if the current is too low, the droplet transfer will be poor, also causing spatter. Therefore, the welding current must be precisely adjusted based on the material and thickness of the steel structure. For example, when welding thicker steel, the current should be increased appropriately; for thinner plates, the current should be reduced. Excessively high or low welding voltage can result in an inappropriate arc length, causing the droplet to deviate from the wire axis or explode in the narrow neck between the droplet and the wire. Therefore, the voltage must be carefully adjusted to ensure stable arc combustion and reduce spatter. The inductance of the welding loop affects the rise and fall rates of the short-circuit current. Excessively high or low inductance can cause the short-circuit bridge to overheat and explode, or even cause a solid short circuit. Adjusting the inductance can smooth the short-circuit current and reduce spatter.
Secondly, selecting the appropriate welding material is crucial for robotic welding workstations. Excessively high or low wire extension length can cause the molten droplet to dwell abnormally at the wire tip, triggering metallurgical reactions or evaporation, leading to droplet explosion or gas escape. Therefore, it is important to ensure the appropriate wire extension length, generally controlled between 10 and 20 mm. Furthermore, high-quality welding wire should be selected to avoid excessively high or low carbon content, which can lead to imbalanced redox reactions in the droplet or weld pool, excessive gas generation, and spatter.
Of course, the proper use of shielding gas is also crucial. Improper shielding gas type, flow rate, pressure, and nozzle can alter the arc's thermal characteristics and oxidizing properties, affecting droplet formation and transfer, and increasing the potential for spatter. For example, the physical properties of CO₂ gas result in a relatively high arc spot pressure, which is the primary cause of spark spatter in CO₂ arc welding. As the proportion of Ar gas increases, spatter gradually decreases. Data shows that Ar + 5% CO₂ produces the least spatter. Therefore, depending on the actual situation, it is important to select an appropriate shielding gas and its ratio, and adjust the gas flow and pressure to ensure uniform and stable gas coverage of the weld area, thereby reducing spatter.
In addition, regular maintenance and cleaning of welding equipment are also important measures to reduce spatter. During welding, spatter accumulates inside the equipment, affecting its performance. Regular cleaning of the equipment, especially key areas such as the welding torch and wire feed mechanism, ensures proper operation and reduces the likelihood of spatter. By precisely adjusting welding parameters, selecting appropriate welding materials, using shielding gas wisely, and regularly maintaining the equipment, robotic welding stations can effectively address spatter issues in steel structure welding, improving welding quality and production efficiency.