Which is better, CO2 welding or manual arc welding with electrodes?

The quality of CO2 welding cannot be guaranteed; shielded metal arc welding uses electrodes that result in a slow welding speed and low efficiency. It depends on the situation; it’s hard to say which is better.

Each of these two methods has its advantages and disadvantages: Carbon dioxide welding is efficient and fast, and it represents a highly energy-efficient welding method; its efficiency is much higher than that of submerged arc welding. The lack of slag protection eliminates the need to remove slag after welding. Additionally, full-position welding can be achieved using thin wires and low currents, making it a low-hydrogen welding method with strong rust resistance and a low hydrogen content in the weld. The disadvantages include significant spatter during welding, especially when the welding parameters are not properly set; it is not suitable for welding in windy areas. The arc light produced during welding is intense, posing a risk to human health, and the equipment is complex, requiring specialized personnel for maintenance and repair. Nevertheless, it represents a significant advancement over traditional manual welding, and it is far superior to manual welding methods.

Each method has its advantages and disadvantages. CO2 gas arc welding is a type of fusion welding method that emerged in the early 1950s; it has since been widely adopted and has become an important fusion welding technique. Its main features include the following: (1) CO2 gas shielded welding is an efficient and energy-saving welding method. For example, when welding 10 mm thick low-carbon steel plates using horizontal butt welding, the power consumption of CO2 gas shielded welding is about 2/3 lower than that of manual arc welding; it is also slightly lower compared to submerged arc automatic welding. Taking into account factors such as high productivity and low material costs, CO2 gas shielded welding is highly economical. (2) When welding with thick wire (wire diameter > ф1.6mm), a higher current can be used to achieve a droplet transfer transition; the current density can reach 100–300 A/mm2. As a result, the melting coefficient of the wire is high, at 15–26 g/(Ah·mm). The penetration depth of the weld joint is also large, allowing for the use of no groove or a shallow groove. Furthermore, this method produces virtually no slag, eliminating the need for slag removal after welding and saving a great deal of labor time; as a result, welding productivity can be significantly improved. When welding with thin wires (wire diameter ≤ 1.6 mm), a lower current can be used to achieve a short-circuit transition mode. At this time, the arc heats the welded parts intermittently; the arc remains stable, heat is concentrated, and the welding heat input is low, making it suitable for welding thin sheets. At the same time, the deformation is very small; no correction process is even required. It can also be used for all-position welding, making it highly versatile. (3) CO2 gas shielded welding is a low-hydrogen welding method with strong rust resistance; the hydrogen content in the weld is extremely low. Therefore, when welding low-alloy steel, it is less likely to cause cold cracks, nor hydrogen pores. (4) The gas and wire used in CO2 gas shielded welding are inexpensive and widely available. Welding equipment has been standardized and produced domestically, creating very favorable conditions for the promotion and application of this method. (5) CO2 gas shielded welding is an open-arc welding method, which facilitates the monitoring and control of the arc and the molten pool, thus aiding in the mechanization and automation of the welding process. It is very convenient to use semi-automatic welding for welding curved welds and welds in spatial positions. Furthermore, compared with manual arc welding, CO2 gas shielded welding also has some disadvantages: first, there is more metal spatter during the welding process, resulting in a rougher weld profile; especially when the welding parameters are not properly set, the spatter becomes even more severe ； Secondly, it cannot be used to weld metals that are prone to oxidation, and it is not suitable for welding in windy areas ； Thirdly, the arc light during welding is quite intense, especially when high-current welding is used; the radiation from the arc is strong, so special attention must be paid to protecting the operators ； Fourth, the equipment is relatively complex and requires a professional team to handle repairs.