Review on Design and Development of Narrow Gap Welding Torches

Narrow gap welding is an effective process for joining thick plates (2" to 12") of carbon steel, low alloys steel and high strength low alloy steels. But it requires some development in torch design, wire feeding mechanism and welding procedure for preventing all sorts of weld defects before practical application. Narrow gap welding technology is associated with various conventional arc welding technology like GMAW, GTAW, SAW, FCAW&SMAW. Several fabricators world over, especially in Japan have developed their own equipment working on different principles [1]

Standard torches for NGW are not available routinely in the market. Torches for NGW are specially designed (custom made) for various NGW applications. Design of torch will differ from processes to process and application to application. Paper highlights the different torch designs used by researcher for different narrow gap welding technologies like

I) Narrow Gap-Gas Metal Arc Welding (NG-GMAW) Torch Design

II) Narrow Gap-Gas Tungsten Arc Welding (NG-GTAW) Torch Design

III) Narrow Gap- Submerged Arc Welding (NG-SAW) Torch Design.