Experimental Validation of Constraint Effects on Toughness Test of Pipeline Girth Welds

Conference paper
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

In the structural integrity assessment or ECA (Engineering Critical Assessment) of pipeline weld defects, one of the most critical inputs is material’s fracture toughness. This toughness is often obtained from standardized fracture toughness tests, such as the CTOD (Crack Tip Opening Displacement) toughness tests frequently used in the oil and gas industries. Given how the specimens are tested, the fracture toughness values from these standardized tests can be lower than the apparent toughness of welds under typical pipeline loading. Consequently, weld integrity assessment using these toughness values can be overly conservative. The difference in toughness between the standardized specimens and pipeline welds can be partly attributed to the constraint effects. In this paper, the constraint effect of X80 pipeline girth weld was studied using SENB (Single edge notch bending), SENT (Single notch tensile) and CWP (Curved wide plate test). The results showed that the level of constraint was affected by the crack depth and loading configuration of the test sample. And the toughness obtained by SENB was more conservative than that achieved by CWP and SENT. In the field of toughness test for pipeline girth welds, CWP and SENT are recommend to be chosen.

Keywords

Pipeline steel Constraint effects Girth weld Toughness ECA 

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Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Sinopec Petroleum Engineering CorporationDongyingChina
  2. 2.Southeast (South–East) Asia Division of CPPLangfangChina
  3. 3.Pipeline Research Institute of CNPCLangfangChina

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