| Abstract |
| The microstructural characteristics of the various low-temperature transformation ferrites such as quasi-polygonal ferrite (α_(B)), granular bainitic ferrite (α_(B)) and bainitic ferrite (α˚_(B)) have been investigated in an ultra-low carbon high strength cold-rolled steel. It was found that a grain of the aB and α˚_(B) comprised several subgrains with orientations of ND//<111> or ND//near <111>, but the aq grain consisted of several subgrains with orientations of ND/ /<001> or ND//near <001>. The EBSD result showed that the α˚_(B) and α_(B) were characterized by low angle grain boundaries whose misorientation angles are smaller than 15˚Even the very low angle grain boundaries with misorientation angle of 2-5˚or less were substantially observed in the α˚_(B) and a_(B) grains, resulting in the not well-etched grain boundaries in optical and scanning electron microscopy. The grain boundaries of the a_(q) were characterized by the high angle grain boundary with a winding shape. (Received September 23, 2004) |
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| Key Words |
| Ultra-Low carbon steel, IF(Interstitial Free) steel, Cold-rolled sheet steel, Low temperature transformation products, Polygonal ferrite, Quasi-polygonal ferrite, Granular bainitic ferrite, Bainitic ferrite, EBSD |
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