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Texture evolution in warm rolled low-carbon steels.

机译:热轧低碳钢的织构演变。

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摘要

The effect of warm and cold rolling parameters on the development of annealing textures and their effects on the final formability were studied in two LC steels containing 0.8%Cr. Warm rolling temperatures between 640 and 750°C were employed, together with reductions of 65% to 80%. The effects of an additional cold rolling reduction of 40%, different initial hot band grain sizes (HBGSs) and a decrease in the heating rate during annealing were also studied. The ND fibre, 111>//ND, of the recrystallization texture was strengthened as the warm rolling temperature was decreased. A noticeable improvement in both the continuity and intensity of the ND fibre was obtained when samples were submitted to an additional 40% cold rolling reduction. The ND fibre was even more continuous and intense when a low heating rate was utilized, yielding r-values of 1.2 and 1.3 for the warm rolled and warm plus cold rolled samples, respectively. On the other hand, the volume fraction of grains containing shear bands is slightly lower for the finer HBGS. However, this does not reduce the amount of in-grain nucleation of gamma grains, suggesting that shear bands are not the only factor that has to be considered in the improvement of warm rolling textures. Although the normal anisotropy is not affected by the HBGS, much lower Deltar values were associated with the finer grained steel.;The texture changes taking place during recrystallization were examined using electron back-scattered diffraction. The recrystallization textures resemble the deformation textures but with a more extensive alpha fibre that includes the {113}471> orientation; the gamma fibre extends to the {554}225>. These two orientations are related to the {112}110> deformed grains by near 26° rotations about selected 110> axes. Nevertheless, both orientations appear in the early stages of recrystallization, an observation that does not support the oriented growth theory. The {111} hkl> orientations are the first to recrystallize while the alpha fibre is present until the end of recrystallization. It is finally consumed by all types of grains as well as by subgrain coalescence. The relatively constant volume fractions of the main orientations and the similarities in the growth rates for the {111} hkl> and random orientations suggest that recrystallization is controlled by the oriented nucleation concept.
机译:在两种含0.8%Cr的LC钢中,研究了冷热轧参数对退火织构的发展及其对最终成形性的影响。采用640至750°C的热轧温度,降温幅度为65%至80%。还研究了额外冷轧减少40%,不同的初始热轧带晶粒度(HBGSs)以及退火过程中加热速率降低的影响。随着热轧温度的降低,重结晶织构的ND纤维<111> // ND增强。当样品进行额外的40%冷轧压下后,ND纤维的连续性和强度都得到了显着改善。当使用低加热速率时,ND纤维甚至更连续且强度更高,热轧和热轧加上冷轧样品的r值分别为1.2和1.3。另一方面,对于较细的HBGS,包含剪切带的晶粒的体积分数略低。但是,这不会减少γ晶粒的晶粒内成核数量,这表明剪切带并不是改善热轧织构时必须考虑的唯一因素。尽管正常的各向异性不受HBGS的影响,但与较细晶粒的钢相关的Deltar值却低得多。使用电子背散射衍射研究了再结晶过程中发生的织构变化。重结晶纹理类似于变形纹理,但具有更广泛的α纤维,其中包含{113} <471>取向;伽玛纤维延伸到{554} <225>。这两个方向与{112} <110>变形晶粒有关,围绕选定的<110>轴旋转了26°。然而,两种取向都出现在再结晶的早期阶段,这一观察结果不支持取向生长理论。在存在α纤维之前,{111} 取向最先重结晶,直到重结晶结束。最终它被所有类型的谷物以及亚晶粒聚结所消耗。主要取向的相对恒定的体积分数以及{111} 和随机取向的生长速率的相似性表明,再结晶受取向成核概念的控制。

著录项

  • 作者

    Sanchez Araiza, Miguel.;

  • 作者单位

    McGill University (Canada).;

  • 授予单位 McGill University (Canada).;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 154 p.
  • 总页数 154
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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