Fracture behaviour of girth welds containing natural defects, comparison with existing workmanship standards

Technical Report · Sun Feb 09 00:00:00 EST 1992

OSTI ID:6779712

Denys, R M ^[1]

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1. Ghent Rijksuiversiteit (Belgium). Lab. Soete

This report describes the results of an investigation into the engineering significance of girth weld defect acceptance criteria based upon weld quality (or workmanship) considerations. To this end, research efforts were divided into a theoretical and an experimental part. The theoretical study involved a comparison of internationally used weld quality standards and codes for pipeline welding in order to identify the general features common to them and to obtain a clear view of the different acceptability criteria. The experimental part was designed to provide factual information on the failure behaviour of defective girth welds in large pipe diameter pipe lines. The focal point of the experimental examinations was to compare, on the basis of wide plate test specimen behaviour, the performance levels of girth welds containing planar weld defects which were grossly out of tolerance with respect to most present-day weld quality (workmanship standards) specifications. The following five types of simulated workmanship-type defects were tested : Incomplete Root Bead Fusion; Incomplete Cap Fusion; Lack of Side Wall Fusion; Elongated Slag (Wagon tracks); Incomplete Root Bead Penetration. The experimental work involved 12 wide,plate tests on defective welded pipe segments taken from 11,2 mm (0,441 in) thick API 5LX70 (Gr. 483 MPa, Cat II) pipes of 762 mm (30 in.) in diameter. All wide plate specimens were tensile tested to failure. In addition to the wide plate tension tests, a series of small scale tests has been performed to enable the applicability of existing fracture mechanics and plastic collapse analyses to be assessed.

• Research Organization: American Gas Association, Inc., Arlington, VA (United States). Pipeline Research Committee; Ghent Rijksuiversiteit (Belgium). Lab. Soete
• Sponsoring Organization: AGA; American Gas Association, Inc., Arlington, VA (United States)
• OSTI ID: 6779712
• Report Number(s): AGA-93007101; CNN: PR-202-009
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
42 ENGINEERING
PIPELINES
WELDED JOINTS
FRACTURE PROPERTIES
DEFECTS
HARDNESS
MATERIALS TESTING
NATURAL GAS
PROGRESS REPORT
STANDARDS
WELDING
DOCUMENT TYPES
ENERGY SOURCES
FABRICATION
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
JOINING
JOINTS
MECHANICAL PROPERTIES
TESTING
032000* - Natural Gas- Transport
Handling
& Storage
420500 - Engineering- Materials Testing