Research on forming limit stress of cold-rolling deep-drawing sheet

The forming limit stress diagram(FLSD),which is stress-based and independent of strain path,has become the hot spot in the research of cold-rolling deep-drawing sheet.In this paper,the cold-rolling deep-drawing sheet SPCEN-SD and DC04 is taken as research subjects.FLD diagram was obtained by rigid die bulge forming experiment.The FLSD diagram was obtained through transforming stress-strain relation under Hill48 yield criterion.The influences of the strain hardening index n and plastic strain ratio r and strength coefficient k on FLSD are investigated.FLSD dependence of n,r and K is discussed.All the data and parameters provide reference basis for practical projects.