Nb-Ti微合金钢的静态再结晶行为

 通过双道次压缩试验研究了Nb-Ti微合金钢的静态再结晶行为,确定了应变诱导沉淀析出前Nb-Ti微合金钢的静态再结晶激活能,并建立了静态再结晶动力学模型。采用面积法及积分-能量法计算的软化率,很好地反映了微合金钢的静态再结晶行为及应变诱导沉淀析出行为。应变诱导沉淀析出的鼻尖温度在900～925℃之间,静态再结晶的临界温度（SRCT）高于950℃。     

微量钼对微合金钢动态再结晶的影响

 通过Nb V Ti和Nb V Ti Mo两种微合金钢在高温(td=900~1 100 ℃)和不同应变速率(=001~10 s-1)下的单道次压缩模拟试验,研究了热变形参数对两种微合金钢的动态再结晶过程的影响,求出动态再结晶形变激活能及相关参数,建立了热变形方程,并通过对比,分析了钼对微合金钢动态再结晶的影响。结果表明：含钼钢的动态再结晶更困难。这是因为钼的自扩散系数大,致使钢具有更高的动态再结晶激活能。     

403Nb叶片钢高温热压缩静态再结晶研究

利用Gleeble-3500热模拟试验机对403Nb马氏体叶片钢进行二道次高温热压缩试验,对不同温度、应变速率、道次间隔下发生的静态再结晶进行了研究和计算,得到403Nb静态再结晶、静态再结晶激活能和静态再结晶晶粒尺寸模型。     

L360管线钢热轧过程静态再结晶行为的研究

奥氏体再结晶行为是影响热轧钢带组织和力学性能的1个主要因素。在热模拟试验的基础上,采用应力松弛法和显微组织观察法,对含Nb和Ti的L360管线钢热轧过程奥氏体静态再结晶行为进行了研究,分析了应变、变形温度、应变速率、原始奥氏体晶粒尺寸对奥氏体静态再结晶的影响。利用线性回归分析,计算出试验钢静态再结晶激活能为203kJ;同时通过回归,得出试验钢热轧过程静态再结晶动力学方程。     

V-N微合金钢Q550D静态再结晶行为

使用MMS-200热模拟实验机研究V-N微合金钢Q550D的静态再结晶行为,获得了其真应力-真应变曲线,同时分析了不同工艺参数对其静态再结晶过程的影响.结果表明：随着变形温度、道次间隔时间、应变量和应变速率的增加,实验钢静态软化率升高.根据实验结果计算得到该钢的静态再结晶激活能为389.4 kJ/mol,回归了静态再结晶动力学模型.     

铌含量对低碳微合金钢回复再结晶行为的影响

采用应力松弛实验研究了低C含Nb微合金钢奥氏体热变形过程中的析出及再结晶动力学过程,通过实验及理论模型分析了析出/溶质拖曳对回复和再结晶行为的影响.结果显示:随Nb含量的增加,析出动力学曲线的鼻尖温度上升,但鼻尖温度对应的时间变化不大,约为20~30s;析出可明显抑制再结晶的发生,增加Nb含量将使非再结晶温度升高;Nb溶质通过拖曳作用阻碍晶界运动,减小了晶界迁移率,最终减慢再结晶过程的发生;对于低C含Nb实验钢,拟合得到再结晶激活能与Nb质量分数的0.5次方成正比.      

钒微合金钢中形变奥氏体的静态再结晶和诱导析出动力学

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     

WNQ570桥梁钢的静态再结晶行为

 为了研究轧制工艺对WNQ570桥梁钢再结晶行为的影响,采用Gleeble-3500热模拟试验机模拟了其双道次热变形过程,测试了试验钢的应力-应变曲线,建立了静态再结晶晶粒体积分数随变形温度和道次间隔时间变化的关系模型,分析了应变诱导析出抑制对静态软化行为的影响。研究结果表明：静态再结晶体积分数随变形温度的提高或道次间隔时间的延长而增大,应变诱导析出抑制静态再结晶的进行;静态再结晶激活能为240.47kJ/mol。研究结果为制订试验钢二阶段控轧工艺提供了依据。     

一种钒氮微合金钢的静态再结晶行为

 通过双道次压缩试验,研究一种钒氮微合金钢道次间隔时间内在奥氏体区变形后的软化行为,采用应力补偿法计算静态再结晶的体积分数,并建立静态再结晶动力学模型。分析变形温度与间隔时间以及钒的析出物对静态软化行为的影响。结果表明,在高于900℃时进行第一道次变形,该钒氮微合金钢很快完成了静态再结晶;在850、800℃变形后的等温阶段,发生了形变诱导析出现象,使再结晶激活能增加,静态再结晶进程受到抑制,导致软化率曲线上出现了平台。     

微合金化钢奥氏体静态再结晶临界温度的确定

本文建立了一种能准确确定微合金化钢奥氏体静态再结晶临界温度（ＳＲＣＴ）（也就是说再结晶开始被抑制的温度）的一种方法。采用扭转试验并应用反椎法）ｂａｃｋ ｅｘｔｒａｐｏｌａｔｉｏｎ）确定了分别含有Ｎｂ，Ｖ、Ｔｉ的三种钢在两种应变（０。２０和０．３５）和若干温度下奥氏体再结晶分数。激活能与温度的倒数的图示表示法使我们能够把每种钢的ＳＲＣＴ确立为应变和奥氏昌粒尺寸的函数。将ＳＲＣＴ与计算的氮化物和碳化物     

冷轧基板SPHE静态再结晶行为研究

 利用Gleeble-3500热力模拟试验机研究了冷轧基板SPHE钢的静态再结晶行为, 通过对奥氏体再结晶行为的研究,得到试验钢发生静态再结晶时变形温度越高,发生静态再结晶越容易。试验钢在900、950和1000℃变形过程中停留不同时间,再结晶分数出现了个别点下降,是试验检测误差所致;随着停留时间的增加,由于溶质原子和碳化物等第二相质点的析出,引起了再结晶速率降低。试验钢SPHE发生静态再结晶的激活能为23987kJ/mol。     

Static Recrystallization Behavior of 316LN Austenitic Stainless Steel

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.     

C-Mn钢高温变形过程再结晶及位错密度的研究

利用Gleeble 15 0 0热力模拟机 ,通过双道次压缩试验 ,计算了C -Mn钢SS4 0 0的热变形激活能 ,建立了静态再结晶模型。模拟计算了因热力学行为的演变引起的静态、动态再结晶以及位错密度等物理冶金现象的变化。研究结果表明 :动态再结晶易在温度较高、应变速率较低的条件下发生 ;静态再结晶在前几道次发生的比较充分 ;粗轧阶段细化晶粒的效果比精轧阶段明显。     

Recrystallization Behavior of Deformed Austenite in High Strength Microailoyed Pipeline Steel

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.     

Recrystallization Behavior of Deformed Austenite in High Strength Microalloyed Pipeline Steel

 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.     

GCr15轴承钢静态再结晶行为

在Gleeble-3800热模拟实验机上利用双道次热压缩的实验方法,获得了GCr15轴承钢在不同实验条件下的应力-应变曲线,研究了该钢种在高温变形道次间隔时间内的静态软化行为以及再结晶规律,模拟材料热加工组织性能,为制定合理的轧制工艺提供实验基础和理论依据。分析了变形温度、应变速率和道次间隔时间对其静态再结晶行为的影响,建立了GCr15钢静态再结晶动力学模型,相应的静态再结晶激活能约为118.72kJ/mol。结果表明:静态再结晶体积分数随变形温度的升高、应变速率的提高或道次间隔时间的延长而增大。     

Static Recrystallization Kinetics Model After Hot Deformation of Low-Alloy Steel Q345B

The static recrystallization behavior of low-alloy steel Q345B during double-pass hot compression deformation tests was investigated in the temperature range of 900-1000 ℃,the true strain range of 0.15-0.25 and the interpass time range of 0.5-50 s on Gleeble-3500 thermo-simulation machine.The results show that static recrystallization during the interpass time is observed.As the deformation temperature and strain increase,softening caused by static recrystallization is obvious.According to the analysis and calculation of thermo-simulation data,the static recrystallization activation energy was obtained and static recrystallization kinetics model was built.Finally,the error analysis of static recrystallization kinetics model proved that the model had good accuracy.Therefore,this model provides a theoretical basis for static recrystallization(SRX)and will contribute to the development of multipass hot rolling process,in order to control the rolling process more accurately.     

低碳钢中铌含量对奥氏体再结晶的影响

为了弄清铌含量对奥氏体再结晶的影响,以低碳钢为研究对象,借助热模拟试验机与金相等分析手段对其进行试验研究与讨论。结果表明,在铌含量一定的条件下,发生动态再结晶的临界应变随着应变速率的增加而提高,随着变形温度的升高而降低;当铌质量分数增至0.05%时,其阻碍动态再结晶的作用更为明显;此外,降低变形量,减少道次间隔时间,提高铌含量,均会使静态再结晶体积分数下降,阻碍静态再结晶的发生。