共查询到19条相似文献,搜索用时 531 毫秒
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1 前言众所周知,冷轧带钢退火的目的是消除冷轧过程所引起的加工硬化,使其重新获得良好的可塑性。一般来说,低碳钢带钢采用一次性退火,其机械性能即能满足交货标准的要求,而高碳钢与合金钢带钢往往要采用一次或多次中间退火。以前, 相似文献
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介绍了不锈钢轧钢厂采用全氢罩式退火和连续酸洗工艺生产Cr13型马氏体热轧不锈钢白皮卷的工艺,重点探讨了罩式退火及酸洗过程中的关键质量控制技术,所生产的钢卷表面质量良好,力学性能指标符合标准要求,一级品率达到98.6%以上。 相似文献
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针对铝管拉伸工艺润滑的特点,分析了乳液润滑剂应具备的性能。协调了乳液润滑剂优良润滑性能与光亮退火性能之间的矛盾。在满足大变形拉伸过程工艺润滑的同时,可使所拉铝管获得光亮退火表面。 相似文献
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本文主要讨论热轧硅钢片在退火中的转变机理。按照一般金属学书上的概念,热轧硅钢片是属于热加工范畴,退火时在组织上晶粒不会发生重建现象。根据我们生产实践观察,热轧硅钢片在退火过程中,是以生核和核长大的方式进行的,它和冷轧钢板一样,也是一个再结晶过程。热轧硅钢片的坯料是由等轴晶粒所组成的,其显微组织如图1所示。图中黑色条状为珠光体,基体是铁素体晶粒。硅钢片经轧制后,则晶粒外形由原先的等轴晶粒改变为向变形方向伸长的所谓 相似文献
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一、前言退火后冷轧薄板的综合性能主要取决于退火工序,而退火工艺制度的制定,则主要是退火温度和保温时间的选择。当然,加热速度和冷却速度在一定的条件下也会影响钢板的性能。冷轧薄板的热处理过程是再结晶的过程,实际上再结晶并不是一个恒温过程,而是一个随着温度升高大致从某一温度开始义在大致某一温度结束的过程。 相似文献
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2试验方案和退火工艺
2.1试验方案
根据前节分析,H68合金属单相α高锌合金,第一再结晶温度低,第二晶粒易长大。结晶理论指出,原始晶粒粗大,加工退火后再结晶晶粒亦大,H68合金在成品冷轧前需经两次中间退火(6.5mm热轧卷坯退火,2.3mm冷轧卷坯退火), 相似文献
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铂丝的微观形貌和位错密度与退火工艺密切相关,研究铂丝退火过程中微观形貌和位错密度的变化,可以优化退火工艺和提高铂丝电阻性能,为研发高性能铂电阻温度计提供支撑。研究表明:初始铂丝表面有黑色斑驳区域和划痕,有自生颗粒和外来颗粒。随着退火时间的延长,铂丝表面的黑色斑驳区域和划痕消失。退火过程中,铂晶粒晶界处的铂原子很不稳定,逐渐与碳原子形成含Pt和C的颗粒,晶界则变宽边深,产生许多孔隙;随着退火时间的延长,铂丝主体中的杂质元素只剩下C。初始铂丝晶粒的内部和晶界处均存在大量的位错,位错密度达到3.69×1012 cm-2,经历退火热处理后晶粒内部和晶界处的位错大量消失。铂丝被充分退火后,位错密度低至无法测出。 相似文献
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二次再结晶的发生会显著改变电工钢带材的组织和织构,进而影响其磁性能。以柱状晶组织高硅电工钢冷轧带材为研究对象,研究了不同退火方法对试样组织和织构的影响,明确了二次再结晶的发生条件、形成机理和控制方法。研究结果表明,柱状晶组织高硅电工钢冷轧试样发生二次再结晶的温度区间为850~1 000 ℃,在900 ℃退火可获得最大的晶粒尺寸。二次再结晶的形成是由于初次再结晶后试样的组织形成了织构抑制作用,小角度晶界抑制晶粒正常长大,大角度高能晶界迁移率高,具有大角度晶界的晶粒以取向长大方式发生二次再结晶。当退火温度高于1 000 ℃时,升温和冷却速率大于5 ℃/min可以有效抑制二次再结晶的发生。 相似文献
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For ultra low carbon (ULC) and low carbon steel (LC), the influence of heating rate, annealing temperature, and holding time on the recrystallisation behaviour and the resulting grain size was investigated. For ULC smallest grain sizes of about 9 μm were obtained at the lowest heating rate whereas for LC significant smaller grain sizes of about 5 μm were determined at the highest heating rate. Furthermore, the evolution of the grain size distribution with varying heating rate, annealing temperature, and holding time was studied in dependence of the rolling and normal direction. The state of the as‐hot rolled microstructure as well as the precipitation state exert a strong influence on the development of the recrystallised microstructure along the different directions for both steel grades. The inherent prolonged microstructure due to the cold rolling process is still obvious just after recrystallisation. With ongoing annealing and grain growth, the aspect ratio approaches the equiaxed state. This change proceeds faster for the ULC steel grade. With increasing annealing temperature, the bimodal character of the grain size distribution disappears and the distribution becomes more homogeneous. 相似文献
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《Acta Metallurgica Materialia》1993,41(11):3089-3095
Investigations of the yield strenght of polycrystalline aluminium have been performed, looking at the effect of recovery annealing after small plastic deformations. The kinetics of the yield strength changes were determined as a function of temperature and time. Results were discussed in relation to electron microscopy observations of changes in the microstructure. It has been found that changes in the yield strength in fine-grained aluminium after small plastic deformations and recovery annealing are controlled by the mechanisms on grain boundaries whereas in coarse-grained aluminium the most important effects are associated with mechanisms in the grain interior. In fine-grained aluminium these mechanisms are: the annihilation of dislocations in grain boundaries which leads to a decrease of the total dislocation density, and the change of the grain boundary characteristics enhanced by this annihilation. In coarse-grained polycrystal the basic mechanisms are rearrangement of tangled dislocations and dislocation walls into subboundaries and growth of subgrains. 相似文献
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C. J. Simpson K. T. Aust W. C. Winegard 《Metallurgical and Materials Transactions B》1971,2(4):987-991
A study of grain growth in dilute cadmium and lead base alloys has revealed that there are four stages of grain growth as
a function of annealing temperature and solute concentration. One of these stages, which can result in a substantial change
in grain size, involves irregular grain growth or secondary recrystallization.
Formerly Graduate Student, University of Toronto. 相似文献
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通过循环预拉伸应变-高温退火制备Al-Cu-Li合金单晶,同时探讨循环预拉伸应变-高温退火过程中预拉伸应变量、循环应变退火次数、应变退火温度对Al-Cu-Li合金晶粒长大的影响以及晶粒长大的过程与机制.研究结果表明,通过循环预拉伸应变退火可以使得合金晶粒异常长大,并且成功制备出厘米级别的宏观粗大晶粒,其长大机理主要为应... 相似文献