Abstract
Crack initiation behaviour of low carbon, manganese steels (containing ferrite, pearlite, and martensite) during wire drawing, was investigated to identify the crack initiation site. The results demonstrated that crack initiation mechanisms were similar to those of ferrite–martensite dual phase steels, at a low drawing strain. Crack initiation by interface decohesion was mainly observed at globular martensite islands or the tip of elongated martensite islands, whereas, that by shear fracture was preferentially observed at elongated martensite islands. Crack initiation by the decohesion of ferrite/martensite interfaces was more frequently observed than that by shear fracture of martensite islands at a low drawing strain. As the drawing strain increased, small martensite islands and other areas such as pearlite/martensite interfaces and the interfaces of pearlite nodules could participate in crack initiation. The results show the importance of avoiding the presence of martensite in order to reduce the incidence of crack initiation during wire drawing.
MST/1868
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