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Gas welding

Joining process where a continuously deposited filling material is melted by the heat created by combustion of acetylene and oxygen.

Illustration of Gas welding

The process

Oxygen [1], and acetylene [2] are supplied to a blowtorch. The mixture is usually made of about 50% acetylene and 50% oxygen but may vary depending on the specifications. The gas mixture is released through the nozzle and ignited, creating a flame, which heats and melts the workpiece surface and then the filler material, usually in the form of a metal rod [3].

The method can be applied in both forward and backward welding. During forward welding, typically used for thicknesses up to 3mm, flame is directed towards (as in illustration) the non-machined surface. For backward welding the gas flame is directed back toward the bonded surface.