共查询到18条相似文献,搜索用时 125 毫秒
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采用MMS-300热力模拟试验机研究了钒和铌-钒微合金钢的静态再结晶规律,绘制了试验钢的静态再结晶软化率曲线,计算出试验钢的静态再结晶激活能并建立了静态再结晶动力学模型,结合沉淀析出物的微观形貌观察,分析了铌对钒微合金钢静态再结晶行为的影响规律。结果表明,铌-钒钢的静态再结晶激活能要显著高于钒钢,在800~950℃变形保温60 s以上的试验条件下,铌-钒钢发生了形变诱导析出,细小的碳氮化物弥散分布在位错及晶界上,使得软化率曲线在此范围内出现"平台",说明铌既限制了静态再结晶的发生,又阻碍了软化行为的进行。 相似文献
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本文绘制了碳氮含量相同、铌含量分别为0.024%和0.058%的两种微合金钢在应变分别为0.20和0.35条件下的再结晶-沉淀析出-时间-温度(RPTT)图。被称为“外推法”的方法被用来确定静态再结昌动力学曲线和绘制RPTT图。作为形变诱导析出行为的结果,在第一种钢的再结晶百分数-时间曲线图中观察到单个平台;第二种钢的这种曲线显示了双平台,以此的解释是用测热法来确认可能有两种形式的析出沉淀。本文使用透射电子显微技术显示在两种钢中形成的析出物形貌和最具有抑制再结晶能力的析出物尺寸。最后,对PRTT图的分析及其所具有的大量信息可提供用以设计一种更为合适的轧制制度,目的在于获得更细小的沉淀析出物和奥氏体→铁素体相变前更好的奥氏体显微组织。 相似文献
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在Gleeable-3800热/力模拟试验机上采用双道次压缩法,研究了一种高Ti微合金钢在奥氏体区变形后道次间隔时间内的静态软化行为,分析了变形温度和间隔时间对静态再结晶行为的影响规律,采用应力补偿法计算了静态再结晶分数。结果表明,变形温度、道次间隔时间对Ti微合金钢静态再结晶行为影响显著,变形温度越高,间隔时间越长,静态再结晶进行得越迅速;确定了Ti微合金钢的静态再结晶激活能为412.56 k J/mol,同时建立了静态再结晶动力学模型。 相似文献
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《钢铁钒钛》2015,(6)
重点研究钒微合金化高锰(20%~30%)TWIP钢的静态软化和应变诱导析出行为,考察了不同钒含量(0.1%、0.2%)和碳含量(0.2%、0.6%、1%)的影响,目标是确定钒在热轧后还能有进一步析出强化作用的条件(如:成分、热加工参数)。在700~1100℃温度范围内进行了双道次扭转试验,还对卷取进行了模拟(从700℃到550℃)。采用先进的分析方法,如通过EBSD来确定晶粒尺寸和再结晶分数,采用TEM来分析析出物。结果表明,在热加工温度范围内,钒的析出相对迟缓,而且只在20%Mn-0.6%C-0.2%V或30%Mn-1%C-0.1%V的成分条件下发生。将碳含量降低到0.2%时,只在650℃和700℃模拟卷取后才能观察到析出物。另外,在有应变诱导析出发生的情况下,回复、再结晶和应变诱导析出之间有着复杂的相互影响。静态再结晶被明显推迟,导致回复对软化动力学具有重要影响。 相似文献
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采用扭转试验和外推法,研究了三种不同含钒量的微合金钢形变奥氏体的静态再结晶动力学,建立了静态再结晶临界温度(SRCT)以上及其以下的温度模型。业已发现,SRCT是应变、奥氏体晶粒尺寸和现合金含量的函数,这里的微合金即指N和V。还对三种钢的应变诱导析出动力学进行了研究,测定了它们的析出-时间-温度(PTT)曲线。测定了未再结晶温度(Tnr),并得出结论,Tnr和SRCT之间差异主要是由于奥氏体晶粒尺 相似文献
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以低碳含磷钢为研究对象,通过分析不同卷取温度(600、650、700℃)时热轧态和冷轧退火态的显微组织、力学性能及退火再结晶动力学行为,对比研究了微铌(0.02%)处理和铌钛复合微合金化(0.02%Nb+0.012%Ti)对钢的组织和性能的影响。研究结果表明,与微铌处理钢相比,铌钛复合微合金化钢在600℃卷取时析出物数量更多,在更高温度卷取时熟化速度更快,650℃卷取时即熟化到一定程度。低温(600℃)卷取时,铌钛复合微合金化钢的退火再结晶更难,800℃×30s连续退火可以保证完全再结晶。将温度继续升高至800℃以上,会导致强度下降,在一定程度上影响板卷之间的性能稳定性。 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
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《钢铁研究学报(英文版)》2011,(Z1):388-392
The Nb-Ti microalloyed high strength IF steel sheet was used to study the effect of annealing temperature on the microstructures,mechanical properties and textures.The experimental results show that experimental steel is incomplete recrystallization at 750℃ annealing,but complete recrystallization from 780℃ to 870℃ under experimental conditions.When the annealing temperature was increased,the yield strength and tensile strength would gradually reduce,the plastic strain ratio and yield point elongation would gradually increase.The yield strength,tensile strength,elongation,the plastic strain ratio and the strain hardening exponent were approximate 300MPa,410MPa,36.5%,1.7 and 0.22 respectively under annealing temperature 810℃ to 840℃.When the annealing temperature was increased,the α-textures and γ-textures were gradually weakened,and the α-textures have a trend to {111} texture.Therefore,the suggestion of the optimal recrystallization annealing temperature is about 810℃ to 840℃ in industrial production. 相似文献
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The dynamic recrystallization (DRX) and static recrystallization (SRX) behaviour of coarse-grained aus- tenite in a Nb-V-Ti microalloyed steel were studied by using a Gleeble thermomechanical simulator. Continuous and interrupted compression tests of coarse-grained austenite were performed in the temperature range of 1000-1 150 ℃ at a strain rate of 0. 1- 5 s 1. The peak and critical strains for the onset of DRX were identified with strain hardening rate analysis, and the ratio of critical strain to peak strain was found to be consistent with the one reported for fine- grained austenite. An equation of the time for 50% softening was proposed by considering the activation energy of steel without microalloying elements and the solute drag effect of microalloying elements. Strain-induced precipitation may not take place at the deformation temperature above 1000 ℃, which indicates that SRX of coarse-grained aus- tenite is mainly retarded by coarse grain size and Nb in solution during rough rolling. 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