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为了控制Q195钢中非金属夹杂物在凝固冷却过程的转变,采用ASPEX自动扫描电镜研究了实际生产凝固冷却过程夹杂物的转变,并用FactSage软件理论计算了这一过程夹杂物转变的热力学原理。研究结果表明:Si-Mn-Al复合脱氧Q195热轧带钢中间包内夹杂物主要成分为SiO2-MnO-Al2O3,连铸坯中硫化物夹杂质量分数急剧升高,氧化物夹杂中SiO2质量分数升高,MnO质量分数下降。钢中夹杂物成分与尺寸有明显对应关系,中间包内夹杂物尺寸越大,Al2O3质量分数越多,SiO2质量分数越低;铸坯中夹杂物尺寸越小,MnS质量分数越高,氧化物夹杂尺寸越小,SiO2质量分数越高。FactSage热力学计算表明,在钢凝固冷却过程,钢中会析出SiO2相、Mn2Al4Si5O18相和MnS相,析出相尺寸一般较小,使小尺寸夹杂物中SiO2和MnS质量分数升高,热力学理论计算可以较好地解释夹杂物成分在凝固冷却过程的转变。 相似文献
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连铸结晶器电磁制动对铸坯中非金属夹杂物影响的研究 总被引:1,自引:0,他引:1
对梅钢2^#连铸机采用的FC-Mold(Flow Control Mold)全幅二段电磁制动器对钢中非金属夹杂物的影响进行了研究。结果表明,采用电磁制动后,铸坯中心的夹杂物总个数少于未采用电磁制动的铸坯,而前者边部的夹杂物个数则是后者的2.06倍;铸坯中心和边部的夹杂物平均直径和平均面积均有所减小,铸坯中心的平均面积减小量达到8.44μm^2。钢中的夹杂物主要为直径全部小于20μm的Al2O3、MnS和CaS夹杂物,还有少量含K、Na的夹杂物。未采用电磁制动的铸坯中含K、Na夹杂物的数量明显多于采用电磁制动的铸坯。采用电磁制动明显降低结晶器液面的波动幅度,这有助于减少卷渣几率。电磁制动使用技术还有待于进一步优化研究。 相似文献
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《热加工工艺》2017,(21)
采用金相显微镜对X80管线钢轧制前后的夹杂物进行了评级和数量统计,用扫描电子显微镜检测了轧制前后夹杂物形态变化,并用能谱分析仪(EDS)分析了夹杂物化学成分。结果表明:铸坯中主要为小尺寸球形夹杂物。铸坯轧制后,D类夹杂物细系的级别值变大,而D类夹杂物的粗系和DS类夹杂物的级别均降低;铸坯试样和钢板试样的1/4位置,夹杂物级别都比较高,在1/2位置,夹杂物级别都比较低;轧制后,小尺寸(3μm)夹杂物的数量增加,大尺寸夹杂物的数量减小。X80管线钢中的夹杂物多为Ca、Mg、Al、O、S等元素组成的硫化物-氧化物复相夹杂,不同类型的夹杂物在不同轧制过程中变形行为不相同。 相似文献
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《铸造技术》2016,(4):744-748
利用金相显微镜、扫描电镜及能谱等手段,对SPHC钢连铸坯在浇注过程中使用电磁制动技术对夹杂物的影响进行研究。结果表明:采用电磁制动技术后,在铸坯宽度方向上,边部夹杂物个数约为心部夹杂物个数的2.00倍、约为距边部1/4铸坯宽度处夹杂物个数的2.08倍。在铸坯厚度方向上,夹杂物数量随位置变化趋势与未加电磁制动是大致相同,仅在距上边部1/4铸坯厚度处夹杂物数量明显降低。从夹杂物总个数角度分析,加电磁制动后铸坯夹杂物总个数略有降低。夹杂物的尺寸均为小于20μm,其形状为圆形、方形、少量三角形和不规则多边形。夹杂物主要类型为Al2O3、铝酸镁类、碳化硅类等。电磁制动对夹杂物的形貌和组成没有明显影响。 相似文献
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通过人工植入夹杂物的方法,采用SEM、EPMA、TEM、纳米压痕和微纳CT研究了FGH96粉末高温合金中30和60μm SiO2夹杂物在粉末态、热等静压(HIP)和热挤压(HEX)过程中形貌、尺寸以及化学成分的演变规律,深入揭示了SiO2夹杂物与基体发生界面反应的机理,定量研究了夹杂物在粉末态、HIP态以及HEX态下尺寸的变化,表征了夹杂物在挤压棒材中的三维形貌。结果表明,在粉末态时,夹杂物呈长条状或板条状;在HIP过程中,夹杂物与基体发生了置换反应,形成了内部Ti O2、外部Al2O3并弥散分布于γ基体的复合夹杂物,确定了形成氧化物的物相种类,揭示了界面反应机理,同时,30μm SiO2周围未出现γ'相贫化区,60μm SiO2周围形成了γ'相贫化区,合金基体较γ'相贫化区具有较高弹性模量和纳米硬度,γ'相贫化区为软化区,反应后30和60μm SiO2夹杂物尺寸分别约为35和75μm,体积得到进一步增大;在挤压过程中,60μm SiO2由于贫化区的存在表现出与30μm SiO2不同的变形行为,并通过SEM观察统计的夹杂物尺寸与理论计算和微纳CT测试结果进行了对比验证。 相似文献
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Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
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After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献
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Z. Sun S.L. Zheng Y. Zhang 《金属学报(英文版)》2007,20(3):187-192
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process. 相似文献
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R. González-Martínez 《金属学报(英文版)》2007,20(4):235-240
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke. 相似文献
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The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
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The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel. 相似文献
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This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before. 相似文献
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Chao Yang He-Fei Huang Massey de los Reyes Long Yan Xing-Tai Zhou Tian Xia De-Liang Zhang 《金属学报(英文版)》2015,28(7):809
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties. 相似文献
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Lei Li Bo Xu Wei-Ping Tong Hui Zhang Chun-Yan Ban Li-Zi He Zhi-Hao Zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui 《金属学报(英文版)》2015,28(6):725
A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed. 相似文献
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综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。 相似文献