Why is CO2 welding more efficient than shielded metal arc welding?

CO₂ gas shielded welding (CO₂ welding) is more efficient than shielded metal arc welding (SMAW) primarily in the following aspects:

**Continuity of Operation**

CO₂ welding utilizes a continuous wire feeding mechanism, allowing for continuous welding for over 30 minutes at a time. In contrast, SMAW requires electrode replacement and slag removal every 13 minutes, with auxiliary time accounting for up to 30%. This continuity significantly reduces non-welding time.

**Energy Utilization and Deposition Efficiency**

CO₂ welding can achieve a current density of up to 200 A/mm² (SMAW only 20-30 A/mm²), increasing penetration depth by 2-3 times, and the deposition rate is 2.5-4 times that of SMAW. Its wire melting rate reaches up to 98%, reducing power consumption per weld by 30%.

**Simplified Process and Cost Savings**

Steel plates thinner than 10mm can be welded directly without beveling. For thicker plates, beveling is reduced by 50%, and the amount of deposited metal is reduced by half. Meanwhile, CO₂ welding requires no slag removal, has a high degree of mechanization, and can save more than 50% in overall costs.

Productivity Comparison

CO₂ welding has a deposition efficiency of 5-8 kg/h, while shielded metal arc welding (SMAW) only achieves 1-3 kg/h, resulting in an actual productivity increase of 1-4 times. In multi-layer welding, the reduced slag removal time further enhances efficiency.