α域熱延した低炭素薄鋼板の集合組織形成に及ぼす成分の影響

Abstract

From a viewpoint of deep drawability, the influence of chemical compositions on the texture formation of steel sheets hot rolled below Ar3 temperature (warm rolled) has been investigated using steels consisting of various combinations of carbon and titanium contents. The formation of texture was greatly influenced by carbon in solution. A steel sheet warm rolled in the absence of carbon in solution revealed strong formation of near ND//<111> orientations in the recrystallization texture. On the other hand, ND//<111> orientations hardly developed and near{113}<110> was recognized as the main orientation of the recrystallization texture when carbon in solution were present. Microscopic studies using transmission electron microscopy and selected area electron diffraction showed that, in the presence of carbon in solution, {114}<110> - {112}<110> orientations were formed in the vicinity of grain boundaries by some unique crystal rotation different from that occurring in the matrix. The occurrence of the unique crystal rotation was explained by the variation of active slip systems caused by work hardening due to the interaction between dislocations and the interstitial atoms. Besides, the influence of grain size before warm rolling and recrystallization temperature on the texture formation, both of which were affected by chemical compositions was also discussed. Finally, proper chemical compositions for producing deep drawing steel sheets by warm rolling were suggested.