Authors: Haibo Xie Zhengyi Jiang W Y Daniel Yuen
Publish Date: 2011/06/28
Volume: 42, Issue: 6, Pages: 1244-1252
Abstract
Edge cracks in cold rolling of the thin strip affect the strip quality and productivity significantly In this study an experimental and mechanical investigation on microstructures has been carried out to study the edge crack formation during cold rolling of the thin strip The effects of the feed material microstructures on the edge crack evolution were studied employing optical microscopy and scanning electron microscopy SEM Experimental observation indicates that fine grain occurs in hotrolled microstructure and coarse grain is produced in ferritic rolled microstructure Different grain sizes affect significantly the formation mechanics of the microcrack crack initiation and orientation of crack extension The grain size and grain boundaries effects on crack retardation are discussed also during edge crack initiation During the crack growth in coarse grain most edge crack tips will blunt which improves the crack toughness by causing less stress concentration Overall the fine microstructure shows a good crack initiation resistance whereas the coarse microstructure has a better resistance to crack propagation This research provides additional understanding of the mechanism of microstructure influence on edge crack evolution of cold strip rolling which could be helpful for developing defectfree thin strip
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