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1.
采用热/力物理模拟和微观分析相结合的方法研究了过共析钢在连续冷却过程中的固态相变和热加工工艺对钢的组织性能影响。结果表明:降低变形温度引起相变温度升高:加快冷却速度,使得相变温度下降;提高变形温度有利于增加抗拉强度,但断面收缩率下降。试验结果用于生产过程优化和控制,使线材的合格率达到95%以上。  相似文献   

2.
利用Thermecomastor-Z热模拟试验机,研究了含铌0.13%微合金低碳钢奥氏体未再结晶区(超过50%、发生再结晶)变形、并以0.1~50℃/s的冷却速度连续冷却过程的相变。研究了热变形参数对相变组织的影响。结果表明,在未再结晶区变形,在连续冷却条件下,冷却速度≥5℃/s时,90%以上组织为粒状贝氏体;在相同变形温度情况下,随着变形量的增加,先共析铁素体的量增加,贝氏体的量随之减少。  相似文献   

3.
奥氏体变形及其对连续冷却相变的影响   总被引:4,自引:0,他引:4  
余驰斌  颜飞  赵刚  陈良  苏毅  胡敏 《钢铁钒钛》2004,25(2):23-26
利用THERMECMASTOR-Z型热模拟实验机,研究了低碳Mn-Nb-Ti微合金钢在高温下的奥氏体变形及其在连续冷却过程中的相变特征,建立了一定变形条件下的动态CCT曲线。实验结果表明,该钢种再结晶温度为950~980℃。当总的变形程度相同时,在相同的冷却速度下,再结晶温度以下累积变形程度增加将对变形后组织的开始转变温度有一定影响。随着冷却速度的提高,相变温度下降。  相似文献   

4.
 建立了热轧低碳Si Mn系TRIP钢相变动力学模型。将该模型用于模拟热轧TRIP钢分段冷却过程中显微组织的演变,并定量分析了热变形和冷却速率对热变形奥氏体相变行为的影响。结果表明,预测值与实测值符合较好;降低终轧温度、提高终轧变形量,延长两相区缓冷时间都能促进铁素体相变,从而有利于提高残余奥氏体中的碳含量。  相似文献   

5.
本文从提高我国输油、输气管线用热轧板卷的韧性出发,探讨了在热轧宽带钢连轧机上生产低碳高强度微合金X60~X65级管线钢的优化控制轧制与控制冷却工艺制度,研究了热变形过程中变形奥氏体的再结晶规律、轧后冷却过程中相变规律,以及整个加热、轧制、冷却、卷取过程中微合金元素碳、氮化物的固溶与析出行为。结果表明,该实验用钢的合理控轧控冷工艺为:奥氏体化温度为1200℃,粗轧区开轧温度为1150℃,终轧温度为1050℃;精轧区开轧温度为950℃,终轧温度为860℃,轧后冷却速度为15℃/s,卷取温度为550℃。采用上述工艺,宝钢生产的X60~X65级管线钢板的冲击韧性值提高了1倍以上,其综合性能达到或接近日本进口钢板的实物水平。  相似文献   

6.
V-Ti微合金化贝氏体非调质钢再结晶奥氏体连续冷却转变   总被引:1,自引:0,他引:1  
用压力膨胀仪测试了一种V-Ti微合金化贝氏体非调质钢热变形后再结晶奥氏体的连续冷却转变动力学曲线,并分析了转变产物的显微组织。实验表明,热变形后该钢不发生先共析铁素转变的临界冷却速度为0.15℃/s。在2-0.03℃/s很宽的冷却速度范围内,贝氏体相变温度在480℃左右,所得到的贝氏体形貌为无碳化无碳化素体与残余奥氏体平行排列的板牺状结构;各种冷却速度下所得的组织均可见少量TiN质点,当冷却速度大  相似文献   

7.
利用Thermecomastor-Z热模拟试验机,研究了铌质量分数为0.128%的微合金低碳钢在奥氏体未再结晶区变形及连续冷却过程的相变,分析了变形温度、变形速率、变形量等热变形参数对相变的影响规律.研究表明,在连续冷却条件下,随着冷却速度的增加,相转变开始点降低,当冷却速率大于5℃/s时,90%以上的组织为粒状贝氏体.变形温度的升高、变形量及变形速率的增加对相变有促进作用.  相似文献   

8.
乔孟平 《宽厚板》2009,15(3):30-33
利用Gleeble-1500热力模拟试验机,研究了典型低碳钢在未变形及变形条件下的连续冷却过程的相变规律,并通过光学显微镜对连续冷却后的组织进行了详细观察和分析。结果表明:随着冷却速度的增加,铁素体相变温度降低,相变时间缩短,晶粒细化,贝氏体含量增多;变形加速了钢的连续冷却转变,使CCT曲线左移,贝氏体的临界冷却速度增加。  相似文献   

9.
一种高性能超低碳钢CCT曲线及组织的研究   总被引:1,自引:0,他引:1  
在Gleeble-3800热模拟试验机上对一种高性能超低碳钢变形奥氏体连续冷却转变曲线(CCT曲线)进行了测定,并观测了不同冷却速度下转变产物的显微组织和硬度。重点研究了以1℃/s和10℃/s冷速连续冷却时的组织转变规律。结果表明:实际生产中,将冷速控制在5—20℃/s之间,开始冷却的温度在650℃以上,此时的相变组织为较均匀的贝氏体组织。  相似文献   

10.
奥氏体状态对Mn-Cr齿轮钢连续冷却相变组织的影响   总被引:1,自引:0,他引:1  
乔兵  王秉新  刘相华 《特殊钢》2005,26(3):25-27
使用Gleeble1500热模拟试验机研究了成分(%)为:0.23C,0.74Mn,0.90Cr齿轮钢奥氏体晶粒尺寸和变形(真应变量0.4)对连续冷却相变组织的影响和连续转变冷却(CCT)曲线。实验结果表明,当齿轮钢未变形时,获得完全多边形铁素体 珠光体混合组织的临界冷速为0.5-1℃/s,冷速较快时,中温相变产物由贝氏体及针状铁素体组成;奥氏体变形时,多边形铁素体相变开始温度升高,获得完全多边形铁素体 珠光体混合组织冷速增大,为1—2℃/s,中温相变产物没有出现贝氏体,只有针状铁素体。  相似文献   

11.
Effects of deformation mode, deformation temperature, deformation rate, cooling rate and slow- cooling stop temperature on the transformation behavior of hot- rolled microalloyed TRIP steel were studied by means of MMS- 300 thermomechanical simulator. The results show that for the samples subjected to the single or double pass deformation, ferrite transformation area is expanded, pearlite transformation area appears, and martensite transformation area disappears in the continuous cooling transformation diagrams. Transformation temperatures of Ar3, Bs and Bf decrease, diffusional transformation is prevented and intermediate temperature transformation is promoted with the increase of deformation temperature or cooling rate. When deformation temperature is 850??, transformation temperatures of Ar3, Bs and Bf increase, the amount of ferrite also increases, and the amount of bainite decreases in the microstructure with the increase of deformation rate. With the decrease of slow- cooling stop temperature, ferrite amount increases, ferrite grains grow and retained austenite amount first increases and then decreases.  相似文献   

12.
ted alot of interests of metallurgical researchers.Aswell known,the steels with ultra-fine grains havepoor work hardening ability and high yield ratio[1].This problem can be solved through complexstrengthening mechanism in which some bainite isintroduced to ferrite matrix with suitable grain size.So it is necessaryto studythe transformation of aus-tenite to bainite inlowcarbon steels during continu-ous cooling after deformation.Most of the research works[2-4]about the trans-formation fromauste…  相似文献   

13.
Deformation affects the microstructure and morphology of the parent austenite, which affects the subsequent bainite transformation. The effects of ausforming on bainite transformation and microstructure were investigated by means of thermal simulation experiment, TEM and SEM etc. Different deformation temperatures and deformation strains were designed. The amount of bainitic transformation during isothermal holding and the volume fraction of retained austenite at room temperature were analyzed. The results show that the isothermal bainitic transformation is promoted by the deformation at 300?? and 400??. Moreover, the lower deformation temperature leads to larger amount of bainite. In addition, the volume fraction of retained austenite increases with the increase of the deformation strain, and more retained austenite can be obtained by decrease the deformation temperature. It indicates that deformation at lower temperature contributes to the mechanical stabilization of austenite.  相似文献   

14.
Utilizing Gleeble-1500 thermomechanical simulator, the influences of hot deformation parameters on continuous cooling bainite transformation in Nb-microalloyed low carbon steel were investigated. The results indicate that bainite starting temperature decreases with raising cooling rate and increases with increasing deformation temperature. Deformation has an accelerative effect on the bainite transformation when the specimens are deformed at 950 ℃. When the deformation temperature increases, the effect of deformation on bainite starting temperature is weakened. The amount of bainite is influenced by strain, cooling rate, and deformation temperature. When the specimens are deformed below 900 ℃, equiaxed ferrites are promoted and the bainite transformation is suppressed.  相似文献   

15.
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   

16.
Thedeformation inducedferritetransformation (DIFT)inthelowtemperatureregioncanbeusedto effectivelyproduceultra finegrainedsteels[1-7]. Thedeformationleadstotheincreaseofstoredener gyandshortenstheincubationperiod.Abovethe pointAr3,ferritetransformationwi…  相似文献   

17.
The hot deformation behaviors and the microstructural evolution of plain C-Mn steels with similar contents of C and Si but different contents of Mn have been investigated by compressive processing using Gleeble-1500 mechanical simulator.Influence of Mn and hot deformation on continuous cooling transformation of steels has been studied.The experimental results showed that deformation in austenite region accelerated transformation process,and the extent is dependent on the hot deformation and cooling conditions.The hot deformation would promote transformation process,but the increase of transformation temperature is dependent on Mn contents.The results have also shown that the effect of deformation on ferrite transformation becomes more obvious with the increase of Mn content at relatively low cooling rate.  相似文献   

18.
颜飞  余驰斌  胡敏  张超 《钢铁研究》2005,33(1):5-7,20
通过模拟试验,测定了Q345E钢的CCT图,确定了不同冷却条件下钢中相变的开始点和终了点,研究了变形量对转变开始点的影响,发现高于再结晶温度时转变开始温度随着变形量的增加而升高,这是变形诱导相变影响的结果。文中还用CCT图曲线对现场冷却过程的相变进行了模拟分析。  相似文献   

19.
变形工艺对微合金高强度钢组织的影响   总被引:1,自引:1,他引:0  
在THERMECMASTOR-Z热模拟试验机上进行了一种微合金高强度钢在不同变形程度、变形速率、变形道次和冷却速度等工艺条件下的热模拟实验.分析比较了不同变形工艺参数对微合金高强度钢相变及组织的影响.实验结果表明,提高轧后的冷却速度使Ar3温度降低;变形速率越大相变开始温度越高;变形程度越大相变开始温度越高.增大变形程度,采用多道次轧制,轧后快速冷却,均有助于铁素体晶粒的细化和减少珠光体的含量.实验钢种的γ+α两相区的温度范围大于140 ℃.  相似文献   

20.
在Gleeble 1500热模拟实验机上进行单道次压缩实验,通过改变变形量以及变形后立即淬火的方法,研究了应变量对微合金钢形变诱导相变上限温度Ad3的影响.还通过不同温度的奥氏体化,研究了铌对微合金钢形变诱导相变上限温度Ad3的影响.结果表明,Ad3随应变量的增大而升高,并且当应变量较大时,Ad3趋于不变;铌对形变诱导相变有强烈的促进作用.  相似文献   

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