Volume 9, Issue 1 (January 1981)
Effect of Understressing and Coaxing on the Fatigue Limit of a Transverse Butt-Welded Joint
A test program was developed to compare both the effects of thermal stress relief and “understressing” and “coaxing” techniques on the predetermined fatigue limits of selected weldments. Approximately 100 specimens were cut from 1025 welded plate and reduced to a finished size of 6.35 mm (0.25 in.) thick by 31.75 mm (1.25 in.) wide by 279.4 mm (11 in.) long. A 6.35-mm (0.25-in.) diameter hole was drilled in the weld to control the failure location. The specimens were subjected to fully reversed bending at selected stress increments until failure occurred. The results indicated that understressing and coaxing produced a marked increase in the effective fatigue limit for all specimens with the most significant increase observed in the specimens that had no thermal stress relief of the weldments. One of the practical applications might be in a case in which a controlled break-in period for welded components is feasible and thermal stress relieving is not.