In the field of welding, the 7018 electrode has long been highly recognized for its excellent welding performance and wide application range. However, a question has always been a hot topic of discussion among welders and industry insiders: when using the 7018 electrode for welding, should AC (Alternating Current) or DC (Direct Current) be chosen? This issue not only relates to the quality of welding results but also affects work efficiency and cost control, thus attracting much attention from the industry.
The 7018 electrode is a low-hydrogen type covered electrode, which is famous for its ability to produce high-strength and high-toughness welds. It is widely used in key fields such as construction, machinery manufacturing, and shipbuilding. Its unique coating composition requires strict control of the welding process to ensure the stability of arc and the formation of welds, and the choice of power supply is a crucial link.
AC power supply, as a common power form in traditional welding, has the advantages of simple equipment and low cost. In some simple welding operations or when the equipment conditions are limited, some welders will try to use AC power to weld with 7018 electrodes. However, it should be noted that the 7018 electrode has higher requirements for arc stability. The current direction of AC power supply changes periodically, which may lead to arc instability during the welding process, resulting in problems such as spatter increase and poor weld formation. Especially for beginners or in welding operations with high quality requirements, the defects caused by AC power supply are more obvious.
DC power supply, on the other hand, provides a stable current direction, which can better meet the needs of 7018 electrode welding. DC reverse polarity (DCEP) is usually the first choice when using 7018 electrodes. Under DC reverse polarity, the arc is more stable, the melting of the electrode is more uniform, and the weld bead is smooth and beautiful. At the same time, stable arc can reduce spatter, improve welding efficiency, and ensure the mechanical properties of the weld. Although the cost of DC welding equipment is generally higher than that of AC equipment, in industrial production with high requirements for welding quality, the advantages of DC power supply in ensuring welding effect make it the preferred choice for most professional welders.
Industry experts pointed out that the choice of AC or DC power supply for 7018 electrode welding should be based on specific working conditions. If it is a temporary, low-demand welding task and only AC equipment is available, experienced welders can try to adjust parameters and adopt appropriate operating techniques to reduce defects. But in formal production and key projects, DC power supply is still recommended to ensure welding quality and reliability.
With the continuous progress of welding technology, some new welding equipment also tries to improve the performance of AC welding for 7018 electrodes through technical means. For example, some inverter-type AC/DC welding machines can optimize the AC output waveform to a certain extent, improving arc stability. However, from the current application effect, DC power supply still has irreplaceable advantages in welding 7018 electrodes.
In general, the question of whether to use AC or DC for 7018 electrode welding does not have an absolute answer, but is closely related to factors such as welding quality requirements, equipment conditions, and operator skills. For most welding scenarios that pursue high quality and stability, DC power supply is the more reliable choice. With the continuous development of the industry, it is believed that there will be more technological innovations in the matching of welding electrodes and power supplies in the future, providing better solutions for the welding industry.