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铁素体不锈钢(FSS)具有良好的成形性能、低成本和耐腐蚀性能,被广泛应用于汽车制造等行业.本文通过对退火态、轧制20%、轧制40%的AISI430铁素体不锈钢进行4h的电化学充氢,研究了变形对汽车用AISI430铁素体不锈钢组织性能的影响和氢脆断裂机理.轧制态铁素体不锈钢具有较高的氢脆敏感性,氢对材料力学性能影响显著,... 相似文献
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冷轧工艺会对铁素体不锈钢的后续退火组织产生重要影响,也是铁素体不锈钢获得良好的表面质量、力学及成形性能的关键.以Nb+Ti双稳定439L铁素体不锈钢为实验材料,采用X射线衍射、微观组织表征以及性能测试等手段,研究了不同的冷轧压下率(60%~85%)对该不锈钢退火过程(1 000℃×2 min)中的微观组织和织构的演变及其力学和成形性能的影响.结果表明:随着冷轧压下率的增加,439L铁素体不锈钢退火后的γ织构不断增强,α织构逐渐消失,即在退火过程中发生了由α→γ织构的转变;同时,随着冷轧压下率的增加,退火织构的峰值强点逐渐向γ取向线靠近,此时439L冷轧退火板的平均塑性应变比(rm)不断增加,在压下率为80%时具有最小的各向异性指数绝对值(|Δr|). 相似文献
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高硅奥氏体不锈钢因其较高的Si元素含量所表现出的优异耐蚀性能而成为制酸行业普遍应用的一种特殊钢种。然而,高含量Si元素的加入会引发铸造缺陷和成分偏析加剧以及钢中析出相增多,热加工过程中易产生热裂纹等问题。高硅奥氏体不锈钢凝固过程中δ铁素体的含量、形态和分布与合金化学成分和热加工历史紧密相关,其室温组织取决于析出相的析出顺序和随后的固态相变,因此,奥氏体不锈钢的凝固模式势必会影响合金的热塑性。为此通过调整高硅奥氏体不锈钢中Si元素与Cr元素的含量,采用金相显微镜(OM)、X射线衍射仪(XRD)、扫描电镜能谱分析(SEM/EDS)、电子探针(EPMA)、JMatPro软件计算等方法,探究了合金成分变化与冷却速率对高硅奥氏体不锈钢凝固模式的影响,并对经典铬镍当量算法进行了评估。结果表明,Schneider铬镍当量算法相较于Rajasekhar铬镍当量算法对大多数合金的凝固模式预测较为准确;随着合金中Si元素与Cr元素含量的提高,合金凝固模式由AF模式转变为FA模式,合金凝固过程中经历更多的“δ→γ”固态相变,其中质量分数为6.0%Si成分的合金对应的δ铁素体增幅减缓;随着质量分数为5.0%的Si铸锭冷却速率的提高,合金凝固模式由AF模式转变为A模式;Hammar and Svensson凝固路线判据可以准确预测高硅奥氏体不锈钢的初始析出相。研究为合理制定高硅奥氏体不锈钢的合金成分与成形工艺提供理论依据。 相似文献
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���ҿ� ��Ӣ�� ���� �ź㿭 《钢铁研究学报》2013,25(12):35-40
Solution treatment and aging treatment of 15Cr23Ni10MoCuV duplex stainless steel was performed at different temperatures. Microstructure evolution and properties of the steel were examined by means of OM, SEM, EDS, XRD analysis, hardness measurement. The results show that a large number of granular chromium carbides can be precipitated in the matrix after hot-rolled, when the solution treatment at 1250?? the chromium carbides will completely dissolved. When solution treated at 1150??, the hardness value of the steel is the lowest. Subject to aging treatments at temperatures of 200-800??, there will be two hardness peaks, corresponding to at 400?? (HB266) and 750?? (HB295). The former is the occurrence of spinodal decomposition in the ferrite and the rich copper phase precipitated in the austenite, while the latter is mainly the emergence of a large number of the ?? phase in the ferrite.. 相似文献
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18Cr-Al-Si铁素体耐热不锈钢作为一种结构连接件的新型材料,主要应用于超(超)临界火力发电领域。为了明确硅含量对该钢组织和性能的影响,以18Cr-Al-Si铁素体耐热不锈钢为成分基础,施以添加2组不同成分的硅含量,通过室温拉伸和高温氧化等试验方法,同时借助金相显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)等表征手段,对不同硅含量试验钢组织和性能进行了系统分析。结果表明,硅含量的增加会细化铁素体的晶粒尺寸并增加M23C6碳化物的数量,试验钢的抗拉强度和屈服强度升高,伸长率下降,断裂方式由韧性断裂向韧-脆混合型断裂方式转变;1.35Si试验钢氧化增重较大,因其钢中析出的M23C6碳化物较多,减少了固溶于基体及形成氧化膜的Cr含量,降低了其抗高温氧化性。 相似文献
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Ѧ���ã���־�գ�֣�Ľܣ��������ν��� 《钢铁研究学报》2013,25(10):36-41
The effect of nitrogen content (0, 0. 095%, 0. 14%, 0. 21%) on microstructure and mechanical properties of 316L stainless steel used in the third generation of nuclear power main pipe was investigated by metallurgical microscope, SEM, TEM, etc. The results show that the grain size of 316L stainless steel can be refined with the addition of nitrogen, especially when the nitrogen content is 0. 095% nitrogen alloying can suppress the precipitation of ?? and ?? phase, and improve the strength, hardness of the 316L stainless steel, and reduce the elongation to fracture, but addition of nitrogen have unapparent impact on the necking rate of the 316L stainless steel, when the nitrogen content is 0. 14%, the tested steel is of best toughness. 相似文献
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Field emission scanning electron microscope and transmission electron microscope combined with energy dispersive spectrometer were used to observe the phosphorus segregation behavior in hot- rolled medium- manganese TRIP steel. The samples were annealed at different temperatures, followed by the same aging process at 560?? for 50h. The results show that particle- like phosphorus is dispersively distributed in the samples annealed at 650??, while the sample annealed at 750?? shows uneven narrow- band- like phosphorus distribution. The entire phosphorus segregation zone overlaps with carbides precipitation. Both 650 and 750?? are intercritical region (ferrite + austenite) temperatures. The segregation usually occurs at ferrite grain boundaries. At the same temperature, the diffusion coefficient of phosphorus in ferrite is 26 times than in austenite. However, it is insufficient to explain the effect of annealing temperature on phosphorus segregation by diffusion coefficient. According to the Kikuchi line analysis in the electron backscatter diffraction, the phosphorus- containing precipitate phase is mainly FeP in orthogonal crystal system and MnxFe1-xP solid solution, which is in accord with the calculation results in Fe- Mn- C- P system by Factsage software. 相似文献
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G. V. Shlyakhova A. V. Bochkareva S. A. Barannikova L. B. Zuev E. V. Martusevich 《Steel in Translation》2017,47(2):99-104
The micro- and nanostructure of 40Kh13 stainless steel is studied by optical, scanning electron, and atomic-force microscopy. The images of the steel’s structure and phase composition in three different states (after annealing, quenching, and high-temperature tempering) are compared. The optical images of the ferrite–pearlite structure with considerable content of (Cr, Fe)23C6 globular carbides obtained after annealing are compared with the results of scanning electron and atomic-force microscopy. It is found that the qualitative conclusions regarding the microstructure of the steel obtained by atomic-force and scanning electron microscopy not only agree with the results of optical microscopy but also provide greater detail. Data from the scanning electron microscope indicate that large carbides are located at the boundaries of ferrite grains. Some quantity of carbides may be found within the small ferrite grains. The size of the inclusions may be determined. The structure formed after quenching consists of coarse acicular martensite. Images from the atomic-force microscope show the acicular structure with greater clarity; three-dimensional images may be constructed. The undissolved carbides are also globular. The size of the martensite plates may be determined. The structure of the steel after high-temperature tempering (tempering sorbite) is formed as a result of the decomposition of martensite to ferrite–carbide mixture, with the deposition of regular rounded carbides. As confirmed by spectral analysis, the individual and row carbides (Cr, Fe)23C6 that appear contain chromium, which rapidly forms carbides. This structure is stronger than martensite. Data from uniaxial tensile tests are presented for all the states; the hardness HB is determined. 相似文献
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采用Formastor-FⅡ全自动相变仪实现不同冷却速度,利用金相显微镜、扫描电子显微镜和透射电子显微镜,研究了45CrMoV钢在不同冷却速度下的组织转变规律以及回火温度对组织的影响。结果表明,随着冷却速度的变慢,45CrMoV钢的组织由马氏体变为马氏体、先共析铁素体、下贝氏体和粒状贝氏体的混合物。冷却速度进一步变慢,先共析铁素体数量增多,下贝氏体和粒状贝氏体总量减少,材料硬度不断下降;45CrMoV钢中的粒状贝氏体为岛状、颗粒状,也有不规则形状,下贝氏体铁素体板条比低碳钢和超低碳钢中的板条更宽,分布更分散,板条形态不规则;随着回火温度的升高,45CrMoV钢中的渗碳体由细针状变为细条状,最后长大为椭球状,材料强度下降,韧性上升。 相似文献
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高硅奥氏体不锈钢由于高含量硅元素的加入使其具有优异的耐高温腐蚀性能和较低的成本,在制酸行业有着潜在的应用价值。然而,该合金中高含量硅元素的加入会促进凝固过程中溶质再分配,进而造成显著的元素偏析,最终导致合金内部产生枝晶组织和大量的有害相。对铸锭组织进行均匀化处理能够有效消除枝晶与元素偏析,促进析出相回溶和枝晶消融,从而改善材料的热塑性,有效应对热变形开裂问题。因此,采用金相显微镜(OM)、扫描电镜能谱分析(SEM/EDS)、电子探针(EPMA)、JMatPro软件计算等方法,研究了实验室条件下制备的5%Si高硅奥氏体不锈钢铸锭的显微组织和元素分布状态,通过残余偏析指数、扩散动力学计算并结合均匀化处理试验验证,最终确定了5%Si高硅奥氏体不锈钢合理的均匀化处理工艺。结果表明,5%Si高硅奥氏体不锈钢凝固过程中钼元素偏析最为严重,通过残余偏析指数模型计算得到的均匀化动力学方程可用来指导该成分合金的均匀化处理工艺;5%Si高硅奥氏体不锈钢经过1 150 ℃×12 h均匀化处理后,铸锭内枝晶消融,元素偏析基本消除,析出相与铁素体回溶到基体中,合金转变为全奥氏体组织,热塑性得到改善;当加热温度达到1 250 ℃时,合金出现过烧现象,晶界开始熔化。 相似文献