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表层细晶化Q235中厚板轧制工艺的研究 总被引:1,自引:1,他引:0
采用Q235成分的连铸板坯,在首钢中厚板厂3300mm轧机上进行了中板表层组织细晶化的工业轧制实验,研究了轧制温度、轧制变形量分配、待温期间冷却方式对板材组织和性能的影响。结果表明,在奥氏体低温区增加精轧总变形量可以实现20mm成品板材的表层组织细化,屈服强度达到300MPa左右,铁素体晶粒达到8.5级,增加待温期间中间坯的水幕冷却有利于整个板材厚度截面的组织细化,屈服强度达到330MPa左右,铁素体晶粒达到9级,材料的强度接近Q345同规格板材的水平,具有优良的塑性和冲击韧性。 相似文献
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利用Gleeble1500-D热模拟试验机,模拟连铸工艺及4道次连轧工艺,对比添加稀土元素Nd对Q345B钢铸坯组织和控轧控冷组织的影响,通过单道次试验分析稀土Nd对动态再结晶、动态激活能的影响。结果表明:Q345B钢中加入稀土元素Nd,能够细化连铸坯的奥氏体晶粒,能够推迟轧制阶段动态再结晶的发生,提高动态再结晶激活能51.3 k J/mol,并对连轧后的控冷组织有显著的细化作用。 相似文献
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采用透射电镜、扫描电镜和能谱分析等方法对Q345E板坯热送裂纹的形成机理进行了分析,研究了Q345E铸坯热送热装工艺对板坯裂纹形成的影响,分析了轧制过程中裂纹的形成机理。结果表明:Q345E铸坯在热送过程中发生奥氏体向铁素体转变,在奥氏体晶界处形成先共析铁素体膜;Nb、Ti的碳氮化物在铁素体中析出并分布在奥氏体晶界处,造成晶界弱化;铸坯在加热炉中受热应力的作用造成Nb、Ti的碳氮化物析出相与先共析铁素体脱离,形成孔洞,为板坯热送裂纹的形成提供了条件。 相似文献
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为解决用户多样化需求与企业连续化生产之间的矛盾,研究了一种采用Q235B普碳钢连铸板坯,通过不同的控轧控冷工艺,分别轧制生产Q235B和Q345B两种强度级别的热轧钢板的工艺。结果表明,通过优化化学成分,采用低温加热制度、低温大压下轧制、快速冷却等控轧控冷工艺,所生产的Q345B钢板内部组织晶粒细化,各项力学性能指标均符合相应标准的要求,实现了Q235B和Q345B两种强度级别热轧钢板的柔性轧制。 相似文献
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以高、中、低3种终轧温度对Q345B热轧钢板进行力学性能和金相组织检测,研究终轧温度对组织和性能的影响。结果表明:随着终轧温度的降低,Q345B钢板的屈服强度和抗拉强度升高,延伸率降低。据此对Q345B钢板的轧制工艺进行调整,提高了产品性能合格率。 相似文献
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在GLEEBLE2000热模拟试验机上进行普通碳锰钢Q345两相区变形实验。研究变形工艺条件对材料微观组织的影响.分析其组织演变规律及机理,并且在实验轧机上进行板材轧制实验。结果表明,实验钢(0.16C,0.3Si,1.29Mn)采用在过冷奥氏体区及其邻近的两相区变形可以获得等轴超细晶铁索体组织;控轧获得的9mm板材铁索体晶粒细化到晶粒截距4μm.抗拉强度580MPa,伸长率29%。 相似文献
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Niobium has an important effect on the transformation behaviour,grain size refinement and precipitation strengthening during hot rolling and subsequent cooling in low carbon steels,with even a low content of niobium having a strong effect on the transformation rate from austenite to ferrite.However,the effects of niobium on transformation behaviour have not been fully characterised and understood to date.This paper examines in detail austenite grain growth as a function of austenitisation time in high strength low alloy (HSLA) steels with three different niobium contents,together with the effect of niobium on the isothermal transformation kinetics from austenite to ferrite as a function of temperature.It is shown that austenite has the slowest grain growth rate in the steel with the highest niobium content.When austenite grain sizes are consistent,the steel with the highest niobium content was found to have the slowest transformation rate from austenite to ferrite. 相似文献
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Modeling of Strain-Induced Precipitation Kinetics and Evolution of Austenite Grains in Nb Microalloyed Steels 总被引:1,自引:0,他引:1
ZHOU Xiao-guang LIU Zhen-yu YUAN Xiang-qian WU Di WANG Guo-dong LIU Xiang-hua 《钢铁研究学报(英文版)》2008,15(3):65-69
Considering the effect of strain and chemical composition onprecipitation behavior, new models for the start and end time of Nb(C,N) precipitation in austenite under the conditions of different temperatures and strains have been investigated for Nb microalloyed steel. The value of n in the precipitation kinetic equation has been determined by using the available experimental data in literature, which indicated that n is a constant and independent of temperature. The values of the start and end time of the predicted precipitation are compared with the experimental values. Calculated results are in good agreement with the experimental results. Also, the evolution of austenite grains before ferrite transformation is simulated by taking the effect of precipitation into consideration. The measured austenite grain size is in good agreement with predicted one prior to ferrite transformation. 相似文献
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快冷条件下钒对中低氮钢晶粒尺寸的影响 总被引:1,自引:0,他引:1
通过实验室轧制试验,研究了中低氮含钒钢在轧后快速冷却条件下的铁素体晶粒尺寸和屈服强度的变化规律.结果表明,加入钒能够细化铁素体晶粒,原因是在快速冷却条件下中低氮含钒钢中的钒全部固溶在基体中,固溶的钒降低铁素体的实际相变温度,从而细化了铁素体晶粒. 相似文献
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Hot torsion testing was performed on a low carbon Nb-Ti microalloyed steel to study the effects of hot torsion parameters, strain and strain rate, on ultrafine ferrite grains production through dynamic strain-induced transformation, at a deformation temperature just above Ar3. The initiation and evolution of ultrafine ferrite grains were studied. The results show that the amount of strain and strain rate has conversely effect on the volume fraction and grain size of ultrafine ferrite grains. With increasing strain, the interior of austenite grains become activated as nucleation sites for fine ferrite grains. As a result, ferrite grains continuously nucleate not only at the former austenite grain boundaries but also inside the austenite grains which leads to a rapid increase in volume fraction of ultrafine grains. Increasing of strain rate reduces the tendency of ferrite grains coarsening so that ultrafine ferrite grains are achieved, while the volume fraction of ultrafine grains decreases at the same strain level. 相似文献