共查询到19条相似文献,搜索用时 140 毫秒
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介绍了调质钢棒材组织性能预报软件的开发和应用情况,模拟了从轧制到调质整个工艺过程中的温度场、轧制负荷、组织性能、热处理效果等。轧制负荷的计算研究中,考虑了奥氏体再结晶软化不充分对轧制负荷的影响。温度场的计算中,实现了VB和ANSYS之间的相互调用,相变量化分析计算中充分考虑了影响CCT曲线位置的因素,并对CCT曲线进行解析化处理,有效提高了组织转变的预报精度。软件的实际应用表明,无论是热轧态还是调质态,组织性能的预报值均与现场实测值基本相符,对改善产品的组织性能,提高产品合格率,具有重要的参考价值。 相似文献
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测定了Al-Zn-Mg-Sc合金固溶处理后的连续冷却转变(CCT)曲线,通过动态电阻法测得冷却过程的电阻-温度曲线,根据曲线斜率的变化规律确定相变开始点、结束点以及临界冷却速度范围,绘制出该合金的CCT图,通过扫描电镜和透射电镜分析观察连续冷却过程的组织转变.结果表明,动态电阻法测得的CCT图是可信的;在470℃,保温1 h固溶处理后,抑制相变发生的临界冷速在2 168.0℃/min以下,但高于716.8℃/min,相变主要集中在150~420℃的温度区间发生;当冷却速度较慢时,平衡相η在晶内和晶界大量析出并逐渐长大和粗化,当冷却速度较快时,合金保持了较高的过饱和度,冷却到70℃以下仍有相变发生. 相似文献
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介绍了几种主要的转炉烟气分析碳含量预报模型,并分析了其中的指数衰减模型及其三种改进算法的基本原理和优缺点。在综合三种模型优点的基础上,提出了基于“极限碳含量拟合+曲线同步更新”算法的改进指数模型。首先,利用历史炉次吹炼后期的脱碳氧效率和碳含量数据,通过指数拟合得到“历史脱碳曲线”和极限碳含量参数;其次,使用当前炉次吹炼中期的最大脱碳氧效率值对“历史脱碳曲线”的特征参数进行替换,得到当前炉次吹炼后期的“参考脱碳曲线”,再对其进行归一化处理,得到归一化的“参考脱碳曲线”;然后,采用多点校正的方法,计算当前炉次吹炼至各等距离校正点时“参考脱碳曲线”的脱碳量,并根据计算脱碳量与转炉实际脱碳量的偏差,对熔池碳含量及脱碳曲线参数进行计算与校正,得到“计算脱碳曲线”;最后,通过逐次迭代计算对“参考脱碳曲线”和“计算脱碳曲线”进行同步更新,进而实现对转炉吹炼后期熔池碳含量的精准预报。研究表明,改进的指数模型具有较高的准确率,终点碳含量预报误差在±0.02%范围内的命中率达到90%。 相似文献
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碳当量是连铸生产实践中分析钢种表面纵裂纹敏感性最常用的方法。为了正确判断连铸过程中钢的表面纵裂纹敏感性,基于表面粗糙度试验对比分析了合金成分和冷却速率对钢的碳当量计算结果的影响。结果表明,合金成分和冷却速率的变化改变了钢种纵裂纹敏感时的碳当量范围。根据凝固过程中冷却速率对钢种纵裂纹敏感性的影响,碳当量计算方法可分为3类,第一类适用于平衡状态下分析碳当量的Yasumoto、BSSTC和Howe公式;第二类适用于传统连铸生产时分析碳当量的Wolf、Trico、Xia和Presoly公式,其中Presoly公式的结果最为可靠;第三类适用于薄板坯连铸生产时分析碳当量的SMS公式。 相似文献
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XU Yun-bo YU Yong-mei LIU Xiang-hua WANG Guo-dong 《钢铁研究学报(英文版)》2007,14(2):66-69
Based on thermodynamics and kinetics, a new mathematical model was developed to calculate the CCT diagrams and the transformation kinetics in low carbon niobium steels, in which the effect of deformation on the degree of supercooling was taken into account. The undercooling caused by deformation is the major reason for the increase of the starting transition temperature during continuous cooling. The critical cooling rate of bainite formation is within 2--5 ℃s for the studied niobium steels and deformation is suitable for the occurrence of pearlite. The ferrite volume fraction increases with the increase of the austenite boundary area, and decreases with the increase of the cooling rate. The calculated CCT diagrams and the volume fraction of each phase are in good agreement with the measurements. 相似文献
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�����ɣ��Խݣ�����Ⱥ�����ˣ��ƽ 《钢铁研究学报》2013,25(8):28-31
The transformation behavior of Nb-V micro-alloyed low carbon austenite steel during continuous cooling was investigated through Gleeble-3800 themomechanical simulator and metallographic analysis. The experimental results show that the dynamic CCT diagrams shift to the left and upper compared with the static ones, the begin temperature of A????-Fe transformation is gradually lower with the increase of cooling rate. The high temperature deformation improves Ferrite and Pearlite transformation and decreases Ferrite transformation zone. When the cooling rate is lower, the deformation improves Bainite transformation; when the cooling rate is higher, the deformation restrains Bainite transformation. 相似文献
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利用Formaster-F全自动膨胀仪测定86CrMoV7钢的过冷奥氏体等温转变曲线(TTT图)中续冷却转变曲线(CCT图),结果表明:在TTT图中存在珠光体、贝氏体、马工体转变,珠光体、贝氏体转变都呈“C”型,有两个鼻点,球光体的“鼻点”温度为625℃,孕育期为50s,贝氏体转变的“鼻点”温度为400℃,孕育期为126s。在CCT图中,只存在珠光体和马氏体转变。 相似文献
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变形参数对S65钢奥氏体相变动力学曲线的影响 总被引:2,自引:0,他引:2
利用Gleeble-1500热/动模拟试验机,研究了变形道次、变形量、变形速率等对S65钢变形后的过冷奥氏体连续却转变曲线(CCT曲线)的影响。根据此研究结果,选择合理的变形参数,制定相应的轧制工艺,可获得S65钢优良的组织性能。 相似文献
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N. Isasti D. Jorge-Badiola M. L. Taheri B. López P. Uranga 《Metallurgical and Materials Transactions A》2011,42(12):3729-3742
Thermomechanical processing of microalloyed steels containing niobium can be performed to obtain deformed austenite prior
to transformation. Accelerated cooling can be employed to refine the final microstructure and, consequently, to improve both
strength and toughness. This general rule is fulfilled if the transformation occurs on a quite homogeneous austenite microstructure.
Nevertheless, the presence of coarse austenite grains before transformation in different industrial processes is a usual source
of concern, and regarding toughness, the coarsest high-angle boundary units would determine its final value. Sets of deformation
dilatometry tests were carried out using three 0.06 pct Nb microalloyed steels to evaluate the effect of Mo alloying additions
(0, 0.16, and 0.31 pct Mo) on final transformation from both recrystallized and unrecrystallized coarse-grained austenite.
Continuous cooling transformation (CCT) diagrams were created, and detailed microstructural characterization was achieved
through the use of optical microscopy (OM), field emission gun scanning electron microscopy (FEGSEM), and electron backscattered
diffraction (EBSD). The resultant microstructures ranged from polygonal ferrite (PF) and pearlite (P) at slow cooling ranges
to bainitic ferrite (BF) accompanied by martensite (M) for fast cooling rates. Plastic deformation of the parent austenite
accelerated both ferrite and bainite transformation, moving the CCT curves to higher temperatures and shorter times. However,
an increase in the final heterogeneity was observed when BF packets were formed, creating coarse high-angle grain boundary
units. 相似文献
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