Development of a Crack Arrest Fracture Toughness Measurement Procedure forQuality Assurance of Plates and Welds Used for Hydrocarbon Storage Tanks. Final Report, October 1986-September 1991

摘要

A test method was developed for measuring the full-thickness crack arrestfracture toughness of steel plates. The method is unique in that it was developed to measure a fracture mechanics parameter for quality control and quality assurance. This was accomplished by designing the test specimen to measure a preselected toughness value. The method is patterned after one developed earlier by MRL that is now an ASTM Standard: E 1221 'Test Method for Determining Plain-Strain Crack-Arrest Fracture Toughness of Ferritic Steels.' Full-thickness cracks, unlike the cracking described in E 1221, frequently form by tunneling, which means that toughness does not have a single value, but is a function of crack length. The feature is accounted for in the method. Full-thickness toughness values are also generally higher than the values measured by ASTM E 1221 so that a plasticity correction is required. Both methods use a static analysis, however, i.e. both methods assume that time dependent affects are negligible. The test method was submitted to the appropriate ASTM Sub-Committee and a Working Group has been organized to promulgate the method as a Standard. Three plates of 9% Nickel steels (A553) having different thicknesses and toughnesses were used for developing the test method. In addition, tests were made on one carbon-manganese-silicon steel (A537) and a hydrogen charged thick plate supplied by Intevep, S.A.