Effects of Residual Tensile Stress on Grooving Corrosion of ERW Pipes

As a special corrosion phenomenon, grooving corrosion often occurs selectively in the welding zone of ERW (Electric Resistance Welded) pipes and forms corrosion grooving. Therefore, it is important to reduce or eliminate grooving corrosion from ERW pipe in many engineering applications [1-2]. High residual tensile stress retains in welding zone of ERW pipes without heat treatment. For example, the residual tensile stress in the circumferential direction of J55 or K55 model ERW pipes may reach about 300 MPa, which is approximately at the same range of their yielding strength. However, the residual tensile stress can be reduced by heat treatment; for example, the residual tensile stress is at the range of 10 to 100 MPa for N80-Q, P110 model pipes. It has been reported that circumferentia