1000MW二次再热汽轮机特大型球墨铸铁件中压外缸的铸造

介绍了1 000 MW二次再热汽轮机特大型球墨铸铁件中压外缸的铸件结构特征、技术要求及生产难点。通过合理的工艺设计、成分选择及生产控制,经力学性能、金相组织、无损检测等检查,中压外缸铸件首次生产即满足技术标准的要求。     

铸造CAE技术在大型球铁件中压外缸产品工艺设计中的应用

介绍了一种大型球铁件中压外缸的铸造结构及技术要求,利用CAE技术,将多种工艺方案可能产生的缺陷问题进行模拟分析,找到产生缺陷的根本原因,并提出了改进方案,解决了中压外缸铸造过程中的缩松与探伤等问题。     

在核电高压外缸上堆焊奥氏体不锈钢耐冲蚀层

阐述了在900MW核电高压外缸上堆焊奥氏体不锈钢耐冲蚀层的工艺方法、生产过程中的具体问题及解决措施。     

在核电高压外缸上堆焊奥氏体不锈钢耐冲蚀层

阐述了在900MW核电高压外缸上堆焊奥氏体不锈钢耐冲蚀层的工艺方法、生产过程中的具体问题及解决措施。     

CAP1400示范工程核电站配套超大型高压外缸铸件铸造工艺研发

根据产品的结构特点，分析了CAP1400核电项目配套超大型高压外缸铸钢件铸造工艺及成型方案的难点，通过在铸件上合理设置冒口和其他工艺信息，利用MAGMA模拟软件，优化了铸造工艺，解决了铸造问题；采用复合成型技术，解决了铸件成型问题。铸件的实际检测结果表明，各项指标均符合要求。     

660MW蒸汽轮机中压内缸铸件研发

以660MW蒸汽轮机中压内缸为研究对象,通过合理设置冒口、补贴,采用冷铁严格分区,保证铸件竖直方向和水平方向的顺序凝固,利用先进的MAGMA软件模拟分析以及优化,并且通过合理的熔炼过程控制、热处理工艺和焊接工艺过程,得到质量合格、组织致密的铸件。     

1080MW核电汽轮机1448mm叶片高频淬火工装设计

通过对1080 MW核电汽轮机组低压缸末级1448 mm动叶片防水蚀高频淬火工艺及工装研究,解决了工装旋转中心的确定、工装结构设计等难题,设计了整体组装结构、调整方便、通用性强的1448 mm动叶片防水蚀高频淬火工装,为实现该叶片的国产化奠定了基础.     

600MW汽轮机组铸钢件高压外缸上、下半的热处理

600MW 汽轮机组高压外缸上、下半铸铜件系属压力容器零件,设计要求的技术条件是比较高的,目前国内运转的机组是由国外引进的。为填补我国机械工业生产中的空白,我厂承接了这一光荣而艰巨的任务。本文叙述了我厂对600MW“高压外缸”铸钢件热处理工艺的研制、生产及其结果。研制热处理工艺过程中的主要依据是:1. 订贷单位提供的技术条件和工艺参数。2. 参考日本的有关资料。3. 结合我厂已生产的200MW、300MW 高、中压外缸上、下半及12500t 热模锻压力机滑块等铸钢件的热处理实践经验。4. 做了各种有关试验及热处理工艺的模拟,取得了600MW“高压外缸”铸件热处理工艺的各项数据,从而编制出了正确的热处理工艺规程。最后,经过生产实践,各项技术指标均达到了设计要求,取得了600MW汽轮机组高压外缸上、下半热处理的成功。     

100万kW核电高中压外缸铸钢件冲击韧度的提高研究

为提高1002rkW核电高中压外缸铸钢件的冲击韧度，通过规范冲击试样加工、细化晶粒、改善微观组织，实现了核电高中压外缸高的综合力学性能，其中冲击韧性AKV均值基本达到顾客标准的2倍以上。     

一种蒸汽轮机中压外缸的铸造工艺方法

主要介绍一种蒸汽轮机中压外缸的铸造工艺方法。该工艺方案由无砂化、低流速的浇注系统,合理的补缩通道,简便的分芯方式组成。该工艺经过凝固模拟验证其可行性,首件生产合格,目前已批量交付。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

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.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

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.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

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.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

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).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

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.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

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.