Investigations of the Short Transverse Monotonic and Fatigue Strengths of Various Ship-Quality Steels
SourceThis paper summarizes a cooperative research program undertaken by the Naval Construction Research Establishment and the Department of Engineering of Cambridge University. It gives a tentative generalized picture of the monotonic and zero-to-tension low cycle fatigue (up to about 5000 cycles) behavior of cruciform welded ship quality plates in range 25 to 76 mm thick. The test results given were obtained over the past few years in a special rig capable of applying loads of 2 MN repeatedly. The rig was designed to accommodate short transverse specimens welded to loading ends so as to apply tension, combined tension and shear, or shear loading, the object being to develop short transverse failures (that is, failures associated with inclusions rolled into the plate). The results indicate the dependence of the short transverse properties on the method of loading, the strength of the steel, and the cleanness of the material. Although there were several forms of failure ranging from deep short transverse tears to failure in attachment welds, which occurred in some of the cleaner steels, it has been possible to rationalize the plots of stress range-logarithm of life to failure in the form of straight lines. This was particularly the case for the tension tests where there was less scatter than for the other two types of test.