WD615柴油机气缸体气孔缺陷的防止

通过改进排气眼，改进浇注工艺，提高型砂性能等措施，较好地解决了气缸体铸件气孔缺陷，使气孔废品率由原来的5％以上降到1．5％以下，取得了较好的效果。     

球墨铸铁阀体缩松缺陷的消除

通过加大冒口，改进冷铁，调整化学成分控制范围，成功地解决了球墨铸铁阀体缩松缺陷问题，使废品率由75％降低到4％。     

Ф22mm棒材生产工艺的改进

针对Ф22mm棒材生产中存在的问题，对生产工艺进行了改进，通过增加轧制道次，改进孔型设计，改善中轧机组电机工作条件，达到了增产节能的目的，产量增加15％。     

数值模拟在曲轴铸件工艺优化中的应用

本文利用微型计算机和数值模拟技术，模拟了６１０５柴油机曲轴的原始工艺及改进工艺后的凝固过程，预测出铸件中收缩缺陷位置与实际情况相吻合。按改进的工艺方案进行生产，使曲轴铸件缩孔、缩松废品率由原来的６％降到３％左右。     

铝合金帽子砂型铸造工艺的改进

通过对帽子铸件结构及原砂型铸造工艺所致铸件缺陷的种类和分布规律的综合分析，改进了原工艺的浇注系统，实现了开放式底注浇注系统横浇道的缓流、过滤、集渣和存贮脏冷铁水的功能；改进了冒口和冷铁设置，提高了顶冒口对铸件顶部热节的补缩作用。通过上述改进，消除了铸件内的夹渣、缩松、冷隔等缺陷，提高了铸件的致密度，使铸件因缺陷和渗漏所致的综合废品率由２０％降到１％。     

微粒高纯三氧化二锑的工业试验研究

将工业用反射式锑白炉进行局部改进，增加烟气加热系统并改进骤冷装置，生产出微粒高纯三氧化二锑，其比表面积大于１１．５ｍ＾２／ｇ，平均粒径小于０．１μｍ，立方晶型大于９９％，白度大于９８％，三氧化二锑纯度大于９９．８５％，酒石酸不溶物小于０．０５％，产率７．８ｔ／ｄ。产品质量与等离子法相当，生产成本却比后者低３０％－４０％。     

改进酚醛树脂液的粘度测量

在树脂磨具制造中，树脂液的粘度是一项重要指标。因此，树脂磨具厂要测量树脂液的进厂粘度及存放过程中的粘度变化。本文介绍了改进树脂液粘度的测量方法和涂4^#杯的结构，以提高测定的准确性，并以测量酚醛树脂液的粘度-温度关系为实例，分析了改进的效果。结果表明，用机械搅拌代替人工搅拌后相对误差可从1．96％降至0．5％，再采用仪器恒温后还能把最大误差从5．40％降至1、80％，     

大型钢烟囱环缝的焊接

主要对一般筒体环缝的焊接工艺进行改进，确保了钢烟囱环缝的焊接质量，焊缝经５０％的超声波探伤，一次合格率达９２．６％，取得了良好的经济效益和社会效益。     

工业合成SiC的节能提质技术及CO收集

碳化硅生产是高耗能行业。本文在简述各种炉体改进和工艺改进的基础上，详细阐述了多热源工业合成碳化硅新技术的节能降耗提质理论及CO回收技术。工业实践表明，三热源合成炉较单热源炉产量提高48．1％，特、一级品率提高30％，节能10％以上，杜绝了单热源生产中频繁喷炉事故，炉体易实现大型化。多热源合成炉炉气中CO含量高达92％，利用新型高温涂塑布气体收集装置收集CO，可提纯利用，生产甲醇进而生产洁净燃料二甲醚。研究成果对于碳化硅工业生产的环境污染控制和提高经济效益具有重要意义。     

提高船板一次性能合格率初探

通过对影响船板一次性能合格率诸因素的分析，根据现场条件，结合规程要求，提出了改进措施，使一次性能合格率由１９９０年的８３．６７％提高到１９９３年的９０．４３％。     

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.     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

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.     

电化学噪声数据处理方法概述

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。