Several electric resistance welding (ERW) processes are available for tube and pipe production. ERW is created by applying a combination of heat and pressure, or forging force, to the weld zone. A successful forged weld uses the optimum amount of heat, which is normally slightly less than the melting point of the material, and a nearly simultaneous application of circumferential pressure to the section, which forces the heated edges together
In this thesis, we discribed main examples and factors of the welding defect in ERW process of pipe production and suggested the optimum welding condition of STKM11A and 16A welding material through nonmetallic containment test, metallic structure test, the state and defect analysis of welding surface etc.