WELD FLAW EVALUATION. Final Report
Investigations were made to determine a basis for the evaluation of the ability of weld flaws to initiate brittle fracture. Studies of brittle fracture mechanics based on the Griffith theory and on Irwin's strain-energy release rate adaptations, static tests on flawed butt welds, static and dynamic tests on small butt weld flaws with and without residual stress, and static tests on weld flaws in a controlled field of high residual stress are reported. All welding flows in selected materials were simulated flaws, varied to represent lack of penetration, porosity, lack of fusion, or sharp intennal weld cracks. Effects of given flaws in various environments were-examined in onder to determine the environment essential to initiate brittle fracture under low static stress conditions. Low temperature was generally an essential part of the environment, but low static stress initiation could not be procured below the nominal yield point unless the static stress was augmented by either a dynamic stress or a high previously- incurred residual stress. The residual stress environment proved to be most significant. Brittle fractures were initiated from short internal cracks with as little as 2000 psi of applied static stress at temperatures in the order of 0 tained F. If total brittle fracture did not result, arrested fractures occurred from small buried flaws, with the arrested crack forming a potential source of fracture initiation. (auth)
- Research Organization:
- Swarthmore Coll., Penna.
- DOE Contract Number:
- NOBS-72060
- NSA Number:
- NSA-14-019389
- OSTI ID:
- 4138538
- Report Number(s):
- SSC-105; PB-161322; Project No. SR-126
- Resource Relation:
- Other Information: Project No. SR-126. Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- United States
- Language:
- English
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