Effect of inadequate joint penetration on fatigue resistance of high-strength structural steel welds
THe University of Illinois and the First Research Center, Japan Defense Agency, collaborated in studies to (1) determine the influence of lack-of-penetration (LOP) defects on the fatigue life of high-strength steel butt welds, (2) determine experimentally the fractions of fatigue life devoted to crack initiation and crack propagation, (3) analytically predict the initiation and propagation portions of fatigue life, and (4) determine the infuence of clustered porosity on total fatigue life. Researchers conducted zero-to-tension fatigue tests where R = 0, R being the ratio of the minimum to maximum stress level on double-butt welds of ASTM A514 steel plate, 0.79 in (20 mm) in thickness, which contained full-length LOP defects. The fatigue crack initiation and propagation portions of fatigue life were experimentally separated. Compression-to-tension fatigue tests were carried out on plane plate, as-welded sound joints, and reinforcement-removed welds to experimentally determine the fatigue-strength-reduction factor (K/sub f/) of the LOP defects. LOP defects as small as 0.02 in (0.5 mm) wide had a profound effect on fatigue life. The fatigue-crack-initiation life appears to be short - only 10% of the total life - and predictable using fatigue-crack-initiation concepts. The use of K/sub f/sub max//, the maximum possible fatigue-strength-reduction factor, proved appropriate.
- OSTI ID:
- 6199368
- Journal Information:
- Weld. J. (Miami); (United States), Journal Name: Weld. J. (Miami); (United States) Vol. 56; ISSN WEJUA
- Country of Publication:
- United States
- Language:
- English
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