Strain aging in low-carbon steels is a well-known strengthening phenomenon, the typical results of which are an increase in yield stress and/or an increase in the extent of discontinuous yielding. Aging effects are generally characterized through the use of results from mechanical tests in which the strain path prior to aging (prestrain) and the strain path after aging are in the same direction. It is well established that when the direction of prestrain and test direction after aging are different, the return of yield point after aging can be delayed or suppressed (1), and the Bauschinger effect can further reduce the yield stress when the test direction is fully reversed. This aging-induced anisotropy of mechanical properties can have significant implications when tensile testing is used to characterize the mechanical properties of an engineered component. In this paper examples will be used from pipeline manufacturing and automotive body-panel stamping to describe how aging effects can cause uncertainty in the use of results from tensile test to characterize engineering properties in components which undergo complex deformation steps during processing.
Citation: Materials Science & Engineering R-Reports
Pub Type: Journals
Strain aging, steel, anisotropy, pipeline, X100, forming, dent resistance