Digital Repository, ECF14, Cracow 2002

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Micromechanics of Fracture in Notched Samples of Heavily Drawn Steel

Last modified: 2013-02-10


This paper deals with the influence of the manufacturing process on themicroscopic fracture behaviour of axisymmetric notched specimens of pearlitic steels withdifferent degrees of cold drawing. To this end, samples from different steps of themanufacturing chain were obtained, from the initial hot rolled material (not cold draw atall) to the final prestressing steel (heavily cold drawn). A detailed fractographic analysiswas performed by using scanning electronic microscopy and image analysis techniques, inorder to define and measure the fracture process zone in each case. Results show that themicroscopic fracture modes range from ductile micro-void coalescence to brittle cleavage,depending on the stress triaxiality generated in the vicinity of the notch tip. A specialfibrous region was detected, which allows a definition of the fracture process zone as thecentral region of the fractured area in bluntly notched samples and the external ring (i.e.,the notch tip) in sharply notched specimens..

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