Electroslag welding
From Wikipedia, the free encyclopedia
Electroslag welding is a highly productive welding process developed in the United States during the 1930s. It involves the melting of the surfaces of the metal workpieces and the filler metal with a molten slag to cause coalescence. An electric arc is passed through the slag to heat it, but the arc itself is extinguished by the slag.
Electroslag welding is commonly used to weld in a vertical orientation, and is particularly popular with steels. In the 1970s, it was used extensively in bridges, ships, and other large metal structures. However, in 1977 the Federal Highway Administration banned its use in welds for some structural members of bridges, due to concerns of weld imperfections and poor properties.
Benefits of the process include its high metal deposition rates—it can lay metal at a rate between 15 and 20 kg per hour (35 and 45 lb/h) per electrode—and its ability to weld thick materials. Many welding processes require more than one pass for welding thick workpieces, but often a single pass is sufficient for electroslag welding. The process is also very efficient, since joint preparation and materials handling are minimized while filler metal utilization is high. The process is also safe and clean, with no arc flash and low weld splatter or distortion.
One electrode is commonly used to make welds on materials with a thickness of 25 to 75 mm (1 to 3 in), and thicker pieces generally require more electrodes. The maximum workpiece thickness that has ever been successfully welded was a 0.91 m (36 in) piece that required the simultaneous use of six electrodes to complete.
[edit] References
- Cary, Howard B. and Scott C. Helzer (2005). Modern Welding Technology. Upper Saddle River, New Jersey: Pearson Education. ISBN 0-13-113029-3.
