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为了研究Nb/V微合金化钢筋的热变形行为,采用 Gleeble-3500热模拟机对Nb和Nb/V微合金化的20MnSi钢进行单轴热压缩试验。通过对其不同形变条件(变形温度和应变速率)下的真应力-应变曲线进行分析,建立可以表征20MnSiNb和20MnSiNbV钢应力、应变、应变速率和温度四者关系的本构方程,并将该本构方程应用于有限元分析软件DEFORM 3D的材料模块中,对试验钢的热压缩过程进行数值模拟。结果表明,2种试验钢的热压缩过程均呈现了明显的动态再结晶特征,Nb或Nb/V微合金化均导致20MnSi钢的热变形激活能增加;有限元模拟表明压缩试样存在应变场和温度场分布不均匀现象,其中试样芯部相对于其他区域始终处于高应变、高应变速率和高形变温度的状态。在实际生产和研究中,对试样不同区域组织和性能的预测可参考模拟结果,分别进行探究。 相似文献
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《稀土》2017,(1)
针对稀土及铌微合金化Fe-3%Si无取向硅钢,在实验室利用Gleeble-1500D热模拟机进行了变形温度为900℃~1100℃、变形速率为0.001 s-1~5 s-1、变形量为60%的单道次热变形实验。分析了不同热变形条件下实验钢的应力-应变曲线以及变形组织,并计算了实验钢的热变形激活能Qd的值。实验结果表明,稀土及铌微合金化Fe-3%Si无取向硅钢在热变形过程中有部分再结晶晶粒出现在原始晶界以及晶界三角地带,但不同变形条件下的应力-应变曲线仍均为动态回复型;热变形激活能Qd分别为449.00 k J/mol、431.59 k J/mol,稀土及铌微合金化可以显著提高Fe-3%Si无取向硅钢热变形激活能,抑制动态再结晶的发生。 相似文献
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通过Gleeble 1500热模拟试验机试验研究了Nb-Ti微合金化低碳钢(/%:0.06C,0.22Si,1.80Mn,0.03Nb,0.15Ti,≤0.007N,≤0.002S)10mm带钢在850~1100℃,以应变速率0.1~20.0 s-1,总变形量75%单道次压缩变形时动态再结晶,由真应力-真应变曲线,结合加工硬化率曲线,得出动态再结晶临界应变0.4~0.7和完全再结晶应变量1.1~1.4。该钢的热变形激活能为618.225 kJ/mol。根据试验结果得到Zener-Hollomon方程和动态再结晶状态图,利用Johnson-Mehl-Avrami(JMA)方程法得到再结晶体积分数实际值,采用Epsilon-P模型对实验数据进行回归,得到试验钢的再结晶动力学模型。 相似文献
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通过对3种不同铌、钒含量的低碳钢进行多道次热压缩变形以模拟中厚板的超细晶轧制工艺,考察了显微组织演变过程、微合金元素和变形条件对组织演变的影响。结果表明:变形过程中有部分奥氏体通过形变诱导相变转变为铁素体;变形并快速冷却后得到平均晶粒尺寸为3~6μm的超细晶组织.铌促进、钒抑制形变诱导铁素体相变,铌、钒微合金化均有较好的细化作用,铌的作用优于钒.再结晶温度以上进行的粗轧有利于精轧时形变诱导铁素体的形成;在精轧温度范围内,增加变形道次、降低道次应变率有利于获得细化的显微组织;降低终轧变形温度对组织细化是最有效的. 相似文献
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利用Gleeble 3800热模拟试验机进行单道次压缩试验,研究了1种新型胀断连杆用高钒中碳钢37MnSiVS在900~1 150℃温度区间和0.1~10s-2变形速率条件下的动态再结晶行为。结果表明:试验料的热变形特征与传统的中碳微合金钢基本一致,较高的温度和较低的应变速率有利于发生动态再结晶。试验料在变形温度低于1 000℃时开始发生再结晶的时间进一步延长。透射电镜(TEM)观察结果表明,试验料中的钒主要以固溶态的形式存在于奥氏体中,从而影响奥氏体的动态再结晶行为。所获得的试验料的热变形激活能为364.9kJ/mol,并得出了其热变形方程及动态再结晶晶粒尺寸与Zener-Hollomon参数之间的关系式。 相似文献
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Recrystallization Behavior of Deformed Austenite in High Strength Microalloyed Pipeline Steel 总被引:3,自引:0,他引:3
Using methods of single hit hot compression and stress relaxation after deformation on a Gleeble 1500D thermomechanical simulator, the curves of flow stress and stress relaxation, the microstructure and the recrystallization behavior of Nb V Ti high strength microalloyed low carbon pipeline steel were studied, and the influence of the thermomechanical treatment parameters on dynamic and static recrystallization of the steel was investigated. It was found that microalloying elements improved the deformation activation energy and produced a retardation of the recrystallization due to the solid solution and precipitation pinning. The deformation conditions such as deformation temperature, strain, and strain rate influenced the recrystallization kinetics and the microstructure respectively. Equations obtained can be used to valuate and predict the dynamic and static recrystallizations. 相似文献
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ZHANG Wen) GUO Xinru) WU Yiping) ZHAO Dewen) ) Shanghai Baosight Software Co. Ltd. Shanghai China ) The State Key Laboratory of Rolling Automation Northeastern University Shenyang Liaoning China 《Baosteel Technical Research》2010,(Z1)
The effect of deformation conditions on dynamic recrystallization behavior of Nb,V,Ti microalloyed high-strength structural steel was investigated via high-temperature single pass reduction tests on a MMS-300 thermomechanical simulator,with mathematical models established for flow stress during hot deformation.The results show that the deformation resistance decreases with the increase of temperature and is in power function relationship with the temperature.Meanwhile,it increases with the increase of st... 相似文献
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Using methods of single-hit hot compression and stress relaxation after deformation on a Gleeble 1500D thermomechanical simulator, the curves of flow stress and stress relaxation, the microstructure and the recrystallization behavior of Nb-V-Ti high strength microalloyed low carbon pipeline steel were studied, and the influence of the thermomechanical treatment parameters on dynamic and static recrystallization of the steel was investigated. It was found that microalloying elements improved the deformation activation energy and produced a retardation of the recrystallization due to the solid solution and precipitation pinning. The deformation conditions such as deformation temperature, strain, and strain rate influenced the recrystallization kinetics and the microstructure respectively. Equations obtained can be used to valuate and predict the dynamic and static recrystallizations. 相似文献
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Using methods of single-hit hot compression and stress relaxation after deformation on a Gleeble 1500D thermomechanical simulator,the curves of flow stress and stress relaxation,the microstructure and the recrystallization behavior of Nb-V-Ti high strength microalloyed low carbon pipeline steel were studied,and the influence of the thermomechanical treatment parameters on dynamic and static recrystallization of the steel was investigated.It was found that microalloying elements improved the deformation activation energy and produced a retardation of the recrystallization due to the solid solution and precipitation pinning.The deformation conditions such as deformation temperature,strain,and strain rate influenced the recrystallization kinetics and the microstructure respectively.Equations obtained can be used to valuate and predict the dynamic and static recrystallizations. 相似文献
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Effect of molybdenum,niobium, and vanadium on static recovery and recrystallization and on solute strengthening in microalloyed steels 总被引:4,自引:0,他引:4
H. L. Andrade M. G. Akben J. J. Jonas 《Metallurgical and Materials Transactions A》1983,14(10):1967-1977
The effect of molybdenum, niobium, and vanadium on the occurrence of static recovery and recrystallization after high temperature
deformation was investigated in a series of microalloyed steels. The steels had a base composition of 0.05 pct C and 1.40
pct Mn. To this, single additions of 0.30 pct Mo, 0.035 pct Nb, and 0.115 pct V were made. Interrupted hot compression tests
were performed at 900 and 1000 °C, and at a constant true strain rate of 2 s-1. The load-free time was decreased from 5000 s to 50 ms, and the degree of static softening during this period was determined.
Both graphite and glass were used as lubricants. Percent softeningvs delay time curves are presented and the retarding effect of molybdenum, niobium, and vanadium addition on the rate of static
recovery and recrystallization is discussed. The greatest solute retardation of static recovery and recrystallization is produced
by niobium addition, followed by that of molybdenum, vanadium leading to the smallest delay. Although the rank order of this
effect is the same as found under dynamic softening conditions, the relative contribution of niobium is more profound for
the static condition. The solute strengthening attributable to each element was also assessed, and found to follow the same
order as for the recovery and recrystallization results. At 900 °C, the onset of the static precipitation of Nb (CN) was detected
at approximately 10 seconds, somewhat earlier than previously reported.
Formerly Graduate Student at McGill University, Montreal, Quebec. 相似文献
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针对微合金化非调质钢热轧过程的变形特征,通过Gleeble-3800热模拟试验机研究了Nb-Ti-V非调质钢C38N2(/%:0.40C、0.52Si、1.42Mn、0.010P、0.047S、0.028V、0.025 Ti、0.022Nb)在950~1 150℃,变形速率0.1~10 s-1变形量60%,单道次压缩时的奥氏体动态再结晶过程,计算得出C38N2钢的动态再结晶晶粒尺寸模型和动态再结晶状态图。结果表明,C38N2钢变形温度越高,变形速率越低,则发生动态再结晶的储蓄能越小,动态再结晶越易发生。C38N2钢的动态再结晶激活能Qd=294.905 kJ/mol。 相似文献
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Dynamic and Static Recrystallization Behavior of Low Carbon High Niobium Microalloyed Steel 总被引:2,自引:0,他引:2
The recrystallization behavior of a low carbon high Nb microalloyed steel was investigated using Continuous and interrupted hot compression tests. The results showed that the onset of dynamic recrystallization (DRX) could be detected from inflection in the plot of the strain hardening rate θ against stress σ regardless of whether the stress peak appears or not. According to Zener-Hollomon parameter the activity energy of DRX (Qdef) was obtained, and a new modified expression calculating Qdef was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method the static softening fraction was determined. The graphic representation of the softening fraction vs. interrupt time gave the information of the non-static recrystallization temperature (about 1000℃)and the relationship of precipitation-time-temperature. Static recrystallization kinetics follow Avrami’s law in high deformation temperature, and different values of the exponent n were given to illustrate the different effects of Nb element on static recrystallization at different deformation temperature. 相似文献