Seam welding is a resistance welding technique used to create a continuous weld, often used for joining overlapping metal sheets, such as in coil-to-coil assembly in continuous processing lines. It relies on heat generated by electrical resistance and pressure to fuse the materials together.
Understanding the Process
Seam welding is a variation of resistance welding. Instead of individual spot welds, seam welding produces a continuous or intermittent weld along a joint. This is achieved by passing overlapping metal sheets between rotating wheel electrodes.
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How it works:
- The metal sheets are overlapped.
- Rotating wheel electrodes apply pressure and pass electric current through the overlapping area.
- The resistance to the electric current generates heat, causing the metal to melt and fuse together.
- The rotating wheels move along the seam, creating a continuous weld.
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Key Characteristics:
- Continuous or Intermittent Welds: The process can create a fully continuous, airtight seam or intermittent, stitch-like welds.
- Overlap Requirement: The process necessitates an overlap between the materials being joined.
- Resistance Welding Family: Seam welding belongs to the resistance welding family, sharing its principles of heat generation through electrical resistance.
Applications of Seam Welding
Seam welding finds use in various industries due to its ability to create strong, leak-proof seals:
- Continuous Processing Lines: A primary application is joining coils of metal together in continuous annealing and galvanizing lines. This allows for efficient processing of long lengths of material.
- Manufacturing Tanks and Containers: The process is used to create liquid-tight and gas-tight seams in tanks, drums, and other containers.
- Automotive Industry: Fabricating fuel tanks and exhaust systems.
- Heat Exchangers: Producing finned tubes and other components.
Advantages of Seam Welding
- High-Speed Production: Seam welding can be a relatively fast welding process, particularly for long, continuous seams.
- Automation: It's easily automated, making it suitable for high-volume production runs.
- Strong and Leak-Proof Welds: The process creates robust welds that can withstand pressure and prevent leaks when performed correctly.
- Cost-Effective: For suitable applications, seam welding can be a cost-effective joining method.
Disadvantages of Seam Welding
- Limited Material Thickness: Best suited for thinner materials due to the heat input requirements.
- Overlap Requirement: The need for overlapping joints can add to material costs.
- Maintenance: The wheel electrodes are subject to wear and require regular maintenance.
