Residual stress on the quality and reliability of welded pipe

Oil and gas transmission pipes - mainly longitudinally welded pipes, spiral seam welded (HSAW) longitudinally welded pipes including UOE welded pipe and JCOE of welded pipe.

Welded steel pipe manufacturing generally after unwinder, straightening, trimming, forming, welding and other industrial processes and testing, flat head, pressure test a series of auxiliary processes. Welded internally there is plastically deformed, and the molding process and the welding process stress applied on the sheet after the molding difficult to all release put, the various types of welded pipe are inevitable presence of residual stress. The presence of residual stress of welded pipe fatigue, corrosion stability, pressure capability has an impact, the residual stress of welded pipe welded pipe manufacturing quality is necessary to ensure the operational reliability of the pipeline.

Welded pipe plays a vital role in the oil and gas transmission. Bending of pipe manufacturing, welding, water pressure, bends, corrosion process, due to residual stress caused by the processing of important factors related to the welded pipe service reliability. The residual stress of welded pipe with its molding. The process has a very large, general Longitudinal a low residual stress levels, evenly distributed, the residual stress level of the spiral welded high, and poor distribution uniformity. Hydrostatic testing and flaring can effectively reduce the residual stress, but the specific parameters of the water pressure and flaring also need to conduct extensive research to determine.