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AP1000核岛主设备中堆芯补水箱内表面均需堆焊不锈钢材料,堆焊层结构为EQ309L(首层)+EQ308L(耐蚀层)。按照设计要求,首层EQ309L熔敷金属需满足铁素体含量为3~20 FN,但在实际制造中发现无法满足该要求。通过研究不同施焊参数下的铁素体含量,发现常用埋弧焊参数无法满足铁素体要求。结合制造过程分析,制定了相应的处理措施,并结合工程实际对后续设计优化提出建议。 相似文献
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奥氏体及双相不锈钢铁素体含量测定方法探讨 总被引:2,自引:0,他引:2
全面介绍了检测奥氏体及双相不锈钢中铁素体含量的三种常用方法:化学分析-图谱法,金相法及磁性法。应根据检测对象选择合适的检测方法。 相似文献
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核电站冷却剂主管道奥氏体-铁素体双相不锈钢铸件中铁素体含量对主管道的使用性能具有重要影响,因此,铁素体含量的检测具有重要意义.本文以主管道90°弯管铸件为例,介绍了铁素体含量检测的各种试验方法,阐明了各种方法的检测原理、检测时机和具体步骤,简要分析了不同检测方法所检测结果的差异和原因,指出了各种方法的适用范围. 相似文献
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铁素体球铁铸件支架在装配时发生脆性断裂失效.通过理化检测试验,对材料的化学成分、力学性能和金相组织做了较为详尽的比较.结果发现,失效件的硅含量偏高、硬度值很不均匀,冲击韧度和伸长率远低于材质要求,因而导致脆断.找出失效原因是铸造工艺不当,并提出合理化建议. 相似文献
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铁素体含量对不锈钢焊缝的裂纹敏感性、耐蚀性和力学性能等有非常重要的影响,铁素体含量的准确预测是指导研发与生产的重要依据。多年来国内外学者和工程师开展了众多研究,其中Schaeffler图、DeLong图、WRC图在不同的历史阶段得到了广泛应用。本文结合预测方法原理,对比了不同方法的技术差异,剖析了Schaeffler图、DeLong图、WRC图铁素体预测图的衍变过程及背景依据,综述了以人工神经网络预测法等为代表的新型预测法原理及发展现状,提出了铁素体预测方法与大数据和人工智能相结合的展望。 相似文献
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赵亮 《热处理技术与装备》2022,(3):25-27
针对不同化学成分的沉淀硬化不锈钢,个别材料热处理后不能满足零件在高速转动下长期稳定使用的要求。本文对其热处理后力学性能和显微组织进行检测与分析,并结合δ铁素体含量预测公式,明确了不同化学成分的沉淀硬化不锈钢在高强度状态下,冲击韧性和δ铁素体含量的关系。对高速转动零件在高强度使用状态下,为不同牌号沉淀硬化不锈钢化学成分的设计提供了一定的技术支持。 相似文献
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采用光学显微镜、扫描电镜、显微硬度计、Thermal-calc热力学软件等设备和腐蚀试验,研究了镍含量对高碳铁素体不锈钢Cr30A铸态组织及耐腐蚀性能的影响.铸态组织分析结果表明,当镍含量低于1.5%时,可以得到铁素体+离异共晶铬系碳化物组织;镍含量高于2.0%时,可以得到铁素体+铁素体/铬系碳化物共析团的组织类型.耐... 相似文献
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INTRODUCTIONPermanentbariumferritematerialsarewidelyused .Recently ,peoplehavepaidmoreattentiontothembecausetheycanalsobeusedasperpendicularmagneticrecordingmediawithhighdensityinnewmagneticrecordingfield[1] andmaterialsactingasconcealmentinarmsindustry… 相似文献
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Ti^4+ substitution for Fe^3+ in Ni0.5Zn0.5Fe2O4 (NZF) ferrite thin films were realized by sol-gel method and annealing at 600℃for 30 min in the air. Crystal structure and lattice constant determination was performed by X-ray diffractometer (XRD). Surface microstructure was observed by scanning electron microscope (SEM) and atomic force microscope (AFM), and the magnetic properties were measured by vibrating sample magnetometer (VSM). XRD analyses of the samples show that Ni0.5+xZn0.5TixFe2-2xO4 (NZTF) films with x varing from 0 to 0.15 in steps of 0.05 are composed of single phase with spinel structure. And the lattice parameter, particle size and the diffraction intensity of the films increase with substitution of Ti as the result of the larger radius ions entering the lattice. SEM and AFM show homogeneous grain size of each sample, but there is a few differences in grain size with different Ti-substitution contents. As the nonmagnetic Ti^4+ substitutes Fe^3+, both the saturation magnetization and coercivity decrease. 相似文献
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The effects of NiO on microstructure and magnetic properties of Mn-Zn ferrite with a nominal composition of Zn0.32Mn0.60-xNixFe2.08O4 were investigated. The calcined powder of Mn-Zn ferrite was characterized by X-ray diffraction (XRD), the fracture surface of Mn-Zn ferrite was checked by scanning electronic microscope (SEM), and then the magnetic properties were measured. As a result, the substitution of Ni can cause the crystallattice constant of MnZn ferrite to decline, and the grain size to decrease, therefore improve the magnetic performance of MnZn ferrite whose density exceeds 5.0 g·cm-3. 相似文献
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以低冰镍为原料,采用草酸盐共沉淀法合成颗粒细小的铁酸镍前躯体 NiFe2(C2O4)3·6H2O。NiCl2?FeCl2?(NH4)2C2O4?H2O体系的热力学研究表明:Ni2+和Fe2+的理论最佳共沉淀pH值为2,2?24C O 对Ni2+、Fe2+离子具有较强的络合作用。在理论研究的基础上,考察沉淀参数对沉淀率和前躯体粒度的影响。结果表明:最佳共沉淀条件为溶液pH=2,反应温度为45°C,(NH4)2C2O4加入量为理论值的1.2倍,PEG400加入量为3%。在此条件下,Ni2+和Fe2+的沉淀率达99.8%,所得前躯体的粒径为1~2 um。XRD和TG?DTA分析表明:所得前躯体为单相置换固溶体,反应过程中镍、铁原子相互取代。 相似文献
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采用物理模拟的方法研究了二次热循环对晶内铁素体的影响。用自动图像分析仪测量了夹杂物的大小、分布和密度,用透射电镜观察了晶内铁素体的形貌,并用能谱对诱导晶内铁素体形核的夹杂物进行了成分分析。研究结果表明,二次热循环对夹杂物的直径大小、分布和密度几乎没有影响。经过二次热循环过程后,诱导晶内铁素体形核、长大的夹杂物为MnO、TiO、SiO2、Al2O3和MnS、CuS、(Mn,Cu)S的复合物。800-500℃的时间为10a时,出现了晶内铁素体的感生形核。晶内铁素体的感生形核是由于一次品内铁素体有较高的界面能和高密度的位错,两者共同促进晶内铁素体的感生形核。 相似文献
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The density, microstructure and magnetic properties of non-doped Mn-Zn ferrite nanoparticles sintered compacts were investigated. The compacts of non-doped Mn-Zn ferrite nanoparticles were sintered by segmented-sintering process at lower sintering temperature. The density of sintered samples was measured by Archimedes method, and the phase composition and microstructure were examined by XRD and SEM. The sintered Mn-Zn ferrite magnetic measurements were carried out with Vibrating Sample. The results show that the density of sintered compacts increases with the rising of sintering temperature, achieving 4.8245 g·cm-3 when sintered at 900 ℃, which is the optimal density of Mn-Zn functional ferrite needed and from the fractured surface of sintered samples, it can be seen that the grain grows well with small grain size and homogeneous distribution. 相似文献
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Study on sintering process and characteristic of nanosized soft magnetic MnZn ferrite powders 总被引:1,自引:0,他引:1
The effect of sintering process (especially the sintering temperature) on the magnetic property and microstructure of sintered sample of nanosized soft magnetic MnZn ferrite powder was investigated. The sintered sample of MnZn ferrite was prepared by both traditional pressing and cool isostatic pressing on MnZn ferrite nanoparticals. The sintering process of which was segmented. Thedensity, microstructure and phase composition of sintered sample were analyzed by Archimedes'law, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The grain growth and densification in sintering process of MnZn ferrite were investigated. The magnetic property was measured by vibrating sample magnetometer (VSM) and Nim2000 magnetic material testing system. The results show that the better sintering temperature is 850 ℃, at which the better magnetic property and microstructure of sintered compact were obtained. 相似文献