共查询到19条相似文献,搜索用时 78 毫秒
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通过双道次压缩实验对首钢迁安公司2160热连轧生产的厚规格X80管线钢形变奥氏体静态再结晶行为进行了研究,依据实验规律对生产工艺进行了改进与优化.通过力学拉伸、冲击及落锤实验,对改进工艺后生产的X80钢的综合性能进行了检测,利用光学显微镜、扫描电镜和透射电镜对X80钢卷显微组织进行了观察分析.结果表明:变形温度是影响奥氏体静态再结晶行为的主要因素;微合金碳氮化物的析出抑制了再结晶的进行,使软化率曲线出现了平台;利用实验结果回归计算出了X80管线钢的静态再结晶激活能为380kJ·mol-1,并根据文献研究讨论了结果的合理性.通过工艺改进与优化,所生产X80钢卷的显微组织细小均匀,呈现典型的针状铁素体特征;析出相中主要包含复合的(Ti,Nb)(C,N)以及单个的NbC;X80钢卷棒状试样的拉伸性能较相关标准均有较大富余量,尤其在冲击、落锤性能方面表现出了良好的低温韧性. 相似文献
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本文采用Gleeble热模拟机,透射电镜和能谱分析等手段研究了复合加入Nb,Ti的低碳锰钢中碳氮化物沉淀和奥氏体再结晶情况。对四种不同成分的钢在925~1075℃之间,以40%应变和10~(-4)~10~(-1)s~(-1)不同应变速率进行等温压缩试验,还分别在不同温度下以相同的应变速率和不同形变量压缩变形后经不同保温时间后水淬,测定钢中碳氮化物应变诱导析出的动力学数据。观察了经热变形试样中沉淀相的形状、尺寸、分布,成分变化及显微组织亚结构等。 研究结果表明:Nb,Ti复合加入,降低了碳氮的活度,增大了微合金元素的固溶度,使沉淀温度降低,析出范围变宽。增加Nb含量,使开始沉淀的时间推迟。奥氏体高温区沉淀的较大质点是以Ti为主的铌钛碳氮化物,较低温度沉淀的细小质点则以含Nb为主。 复合加入Nb,Ti,提高了奥氏体再结晶激活能,从而有效地抑制了再结晶的发生,其阻滞作用比单独加入时大。这种效应是由溶质原子的拖曳机制和其碳氮化物沉淀机制共同完成,但在高温奥氏体区,固溶阻滞机制起主要作用。 相似文献
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利用GleebIe-1500热模拟实验机研究23Co13Ni11Cr3Mo超高强钢高温变形道次间隔时间内的静态软化行为,讨论变形温度、应变速率、变形程度、间隔时间及初始奥氏体晶粒尺寸等对其静态再结晶行为的影响。结果表明:变形程度对23Co13Ni11Cr3Mo钢的静态再结晶影响最大,增大变形量可获得均匀细小的晶粒组织;变形温度和间隔时间次之;应变速率及初始奥氏体晶粒尺寸的影响较小。根据实验结果,建立23Co13Ni11Cr3Mo钢静态再结晶晶粒尺寸模型,定量分析起落架在锤锻压机上整体模锻成形过程的组织演化,发现在变形不充分的条件下静态再结晶是导致起落架锻件晶粒不合格的原因。模型预测结果与实验结果吻合较好。 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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低碳钢热变形奥氏体的再结晶行为 总被引:2,自引:0,他引:2
对热变形奥氏体的再结晶动力学和微观组织演变进行了模拟计算,对晶粒尺寸的模拟值和实测值作了比较,分析了化学成分对动态再结晶率的影响以及残余应变与变形温度的关系.结果表明:在温度较高、应变速率较低的条件下容易发生动态再结晶,随着变形温度的降低,发生动态再结晶的几率减小,而静态再结晶在前几道次进行得比较充分,随后进行得不充分,增加碳和锰的含量可以促进动态再结晶的发生,残余应变随变形温度的降低而增大,晶粒尺寸的模拟值和实测值吻合较好,表明所选用的模型有一定的参考价值. 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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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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The static recrystallization of 316LN austenitic stainless steel was studied by double-pass hot compression tests on a Gleeble-3500 thermomechanical simulator. The specimens were compressed at the deformation temperatures of 950, 1050, 1150 °C, strain rates of 0.01, 0.1, 1s?1, strains of 0.1, 0.15, 0.2, and intervals of 1 — 100 s. The results show that the volume fraction of static recrystallization of 316LN increases with the increase of deformation temperature, strain rate, strain and interval, which indicates that static recrystallization occurs easily under the conditions of higher deformation temperature, higher strain rate and larger strain. Deformation temperature has significant influence on static recrystallization of 316LN. The volume fraction of static recrystallization could easily reach 100% at higher deformation temperatures. By microstructure analysis, it can be concluded that the larger the volume fraction of static recrystallization, the more obvious the grain refinement. The static recrystallization activation energy of 317 882 J/mol and the exponent n of 0.46 were obtained. The static recrystallization kinetics was established. The predicted volume fraction of static recrystallization is in good agreement with the experimental results. 相似文献