Uniform deformation of tempered copper alloy sheets is small, and their bend formability depends largely on the amount of non-uniform deformation, which is complicatedly influenced by other factors in addition to the work-hardening exponent n. In this study, it has been shown that post-uniform elongation in the tensile test can be represented by two parameters, (e f − e u ) and f . The symbol e f is the nominal strain at the breakage point, e u the uniform elongation and f the parameter giving the degree of strain localization along the tensile axis. Good correlation between those parameters and bend formability was ascertained by experimental studies on C51900 and some other Cu alloy sheets. The experimental results showed that the introduced two parameters were not independent variables but mutually related. In addition, the nucleation and growth processes of surface wrinkles in bending, which finally led to cracking, were studied metallographically. A lot of micro necks first arose in the vicinity of grain boundaries, and part of them developed into the groove of wrinkles. Spacing between grooves appeared to correspond with the size and distribution of cube-oriented grains.
Low cycle fatigue tests of the dissimilar metal electron beam welded joints between A387, Gr. 22 steel and SUS 405 steel (A387-SUS 405), and between A387, Gr. 22 steel and SUS 316 steel (A387-SUS 316) were carried out under the strain controlled cycling over the welded joints at a temperature of 839K.It was shown that the fatigue lives of the dissimilar metal welded joints were significantly shorter than those of base metals.In order to discuss the fatigue fracture behavior, the distribution of local strain and that of hardness were investigated.In A387-SUS 405, the strain concentration occurred on SUS 405 side during all strain cycling.While in A387-SUS 316, the uniform strain distribution was produced at the early stage of strain cycling, and thereafter the strain concentration occurred on A387 side.The change of strain distribution with strain cycling qualitatively corresponded to that of hardness. From the foregoing results, it was concluded that the shorter fatigue lives of the dissimilar metal welded joints resulted from the strain concentration which occurred on the base metal with lower deformation resistance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.