In the gas shielded welding process, gas is a crucial parameter that is often overlooked. Traditionally, many believe that the cost of welding production is primarily determined by the procurement cost of consumables, assuming that lower costs are always better. However, with technological advancements, modern welding production focuses on using new technologies to boost efficiency and reduce overall costs. Despite only accounting for about 5% of total welding costs, the shielding gas significantly impacts the welding process and final results.
Common protective gases used in welding include argon (Ar), carbon dioxide (COâ‚‚), and sometimes oxygen (Oâ‚‚), hydrogen (Hâ‚‚), helium (He), or nitrogen (Nâ‚‚) are added to enhance the process. Table 1 outlines the physical properties of these gases, which directly influence their behavior during welding. The development of shielding gas is based on the combined application of these properties.
The role of welding protective gas is vital from a technical perspective. By adjusting the gas composition, five key benefits can be achieved:
1. **Increased wire deposition rate**: Argon-rich mixtures typically offer higher productivity compared to pure COâ‚‚. To achieve jet transition, the argon content should exceed 85%. Proper selection of welding parameters is essential to maximize efficiency and avoid post-weld slag.
2. **Control of spatter and improved arc stability**: Using certain gas mixtures can reduce spatter and improve arc stability, especially when paired with advanced power technology. This helps expand the welding parameter window and improve overall performance.
3. **Better weld formation**: Argon mixtures help control weld shape, reducing excessive weld metal and saving material. This leads to cost savings and better aesthetics.
4. **Higher welding speed**: With argon-rich gas, welding speed can be increased while maintaining good control over spatter, particularly beneficial in automated welding systems.
5. **Reduced fumes**: Argon-rich mixtures significantly lower welding fumes compared to COâ‚‚, offering environmental benefits without requiring costly hardware upgrades.
In summary, selecting the right shielding gas enhances welding quality, reduces costs, and improves efficiency. While argon-based mixtures are widely used, especially in industries like automotive manufacturing, many domestic companies still rely on 80% Ar + 20% CO₂, which may not always be optimal. Choosing the best gas is one of the most effective ways to improve production management. Additionally, maintaining an appropriate gas flow rate is critical for weld quality—too high or too low can negatively impact the process.
**Typical Products**
1. **Stargold Binary Argon Mix**: Known for its stable arc, clean weld surface, and minimal spatter, this gas eliminates the need for post-weld polishing. In some auto parts applications, it reduces oxide scale, improving paint adhesion. As shown in Figure 1, Stargold 5 provides a smooth, clean weld surface without splatter.
2. **Robostar Ternary Gas**: Ideal for automatic welding, Robostar offers strong penetration, high efficiency, and excellent joint fatigue strength. It's suitable for various droplet transfer modes and helps prevent stress concentration at the weld-to-base metal interface, as seen in Figure 2.
3. **Stargon**: Compared to CO₂, Stargon increases welding speed by 20–30% and reduces fumes by 50–100%, making it an environmentally friendly option. It ensures a stable process and well-formed welds, as demonstrated in Figure 3.
For materials like stainless steel and aluminum alloys, specific gas options are available. Table 2 provides recommendations based on base metal thickness.
**Future Outlook**
As new welding processes and materials emerge, shielding gases continue to evolve. Future developments will focus on increasing welding speed, improving efficiency, and reducing fumes. While selecting the best gas is important, it must be paired with appropriate welding parameters to achieve optimal results. Modern gas suppliers now act as full-service solution providers, integrating gas application into broader welding technology strategies.
The China Welding Technology Center, part of Praxair’s global research network, has dedicated years to advancing these technologies, applying lab findings directly to real-world production settings.
For all welding enterprises, improving efficiency, product quality, and process optimization are key directions. A small change in shielding gas can have a significant impact on the entire welding operation. Understanding how to use gas effectively is crucial for every company. Collaborating with leading gas producers and optimizing welding parameters is the path to achieving efficient and high-quality production.
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