共查询到18条相似文献,搜索用时 67 毫秒
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在Gleeble热模拟试验机上,研究含铌微合金钢中铌的析出物在形变诱导相变过程中的作用机理,结果表明:当加热温度为1000℃时,部分铌的碳化物未溶解于奥氏体中,而加热温度为1100℃时,铌的碳化物能够全部溶解到奥氏体中,含铌微合金钢加热温度范围约在1000~1100℃之间。铌的未溶解碳化物和在冷却过程中析出的碳化物都能作为铁素体形核位置,从而促进γ→α相变的发生。 相似文献
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变形速率对普碳钢中形变诱导铁素体相变的影响 总被引:1,自引:0,他引:1
针对普通碳素钢(Q235类型),研究在Ae3~Ar3温度区间内采用形变诱导铁素体机制获得超细晶铁素体的数量与变形速率的相互关系。实验在Gleeble 1500热模拟实验机上进行。实验方案为:1000℃保温2min,以10℃/s的速度冷却到变形温度[Ae3(840℃)至Ar3(780℃)],变形量为30%~50%,变形后立即水淬。结果表明,在840℃变形时,随着变形速率的增大,形变诱导铁素体量增多;在780℃变形时,随着变形速率的增大,形变诱导铁素体量减少;而在840-780℃之间变形时,变形速率存在最佳值,在该值下诱导生成的铁素体量最大。 相似文献
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采用热力模拟实验技术、OM、SEM及TEM,并结合宏观硬度测试,研究了V-Ti微合金钢形变奥氏体的连续冷却相变和组织演变规律,建立了实验钢连续冷却转变曲线,并探讨了第二相的析出行为。结果表明,不同冷速下,实验钢获得了不同的微观组织,同时第二相的形貌、尺寸也发生了变化。 相似文献
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本文不仅详细阐述了铌钢产品中钢成份的发展趋势,铌对钢材机械性能的优化效果及其产品的加工性能,还提到了用铌来代替其它微合金化元素的潜在的发展领域。最后给出了市场供给和需求及价格波动特性,并进一步讨论了期望“价格稳定”的原因。 相似文献
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铌微合金钢中碳氮化铌化学组成的计算与分析 总被引:6,自引:2,他引:4
采用由热力学计算方法导出的二元微合金碳氮化物化学组成的理论计算公式,对一系列铌微合金钢中在奥氏体中沉淀析出的碳氮化铌的化学组成进行了实际计算,计算结果与有关文献给出的实验结果基本吻合。计算结果表明,碳氮化铌中碳化铌的摩尔分数x随温度的变化曲线一般为具有一极大值的连续上凸曲线;钢的化学成分中C量升高将使x增大,N量升高将使x减小,Nb量升高将使x增大;C、N量升高将使x取极大值的温度升高,而Nb量升高将使该极值温度降低。 相似文献
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The accurate prediction of soluble Nb content during reheating is helpful for the design of chemical composition and reheating parameters for Nb-containing steels.The dissolution behavior of Nb in high Nb microalloyed steels was investigated.The results show that Nb does not entirely dissolve for high Nb microalloyed steels containing Ti after holding at 1 300℃ for 3h.The soluble Nb content increases with the decrease of C content and/or the increase of Nb content in steels.Moreover,an expression has been established to describe the amount evolution of soluble Nb in high Nb microalloyed steels during reheating and the validity of this expression has also been verified by experiment. 相似文献
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利用GLEEBLE-2000对试验钢进行热模拟试验,并结合显微硬度测试,研究了一种Nb-Ti微合金钢热变形奥氏体的变形后冷却相变行为.利用JEM-2000FX电镜对碳膜萃取复型法获取的第二相析出物进行分析,从而对热变形后冷却相变中的第二相析出行为进行了研究,探讨了不同冷却速度对第二相析出的影响,结果表明,有大量弥散分布的细小粒子析出,析出相主要以Nb-Ti碳氮化物复合相形式存在,一般呈方形、椭圆形、圆形以及不规则形状,并且随着冷却速度的增加,第二相析出增多且变得细小. 相似文献
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Susceptibility of the steel for further cold processing strongly depends on the whole prior history of deformation in the hot working regime.In the industrial hot working processes,e.g.at the roughing stage of hot rolling,or forging,material undergoes complex deformation modes that leads to gradients of both microstructure and properties across the deformed cross-section.Torsion and multiaxial compression tests with different amounts of strain reversals were conducted at elevated temperatures to study the effect of applied strain path on the phenomena occurring during microstructure evolution of Nb-microalloyed steels.Gathered results will provide data for the modification of existing constitutive equations that mostly do not account for the strain path changes.Better through-process modelling will then enable to achieve better properties and quality of the products for further cold processing. 相似文献
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Precipitation kinetics of Nb(C,N) in microalloyed steels is crucial for the achievement of favoured steel properties. Therefore, numerous experimental studies have been performed in the past and various theoretical models have been developed to describe Nb(C,N) precipitation. However, the experimental data is sometimes contradictory and even the thermodynamic data for NbC solubility in austenite have a large scatter. In this paper, experimental results on the Nb(C,N) and NbV(C,N) precipitation kinetics in deformed and undeformed austenite are reviewed. Based on these data and with the precipitation kinetics module of the software package MatCalc, computer simulations are performed. The predicted interfacial energy of precipitates is adjusted to match the observed kinetics. A comparison between experimental information and simulation, i.e. time ‐ temperature ‐ precipitation (TTP) diagrams, is drawn and discussed. The results of the computer simulations using modified interfacial energies are in good agreement with the experiments. 相似文献