变质处理对硼铬系合金铸铁磨球组织及性能影响的研究

采用ＳＱＹ－４型变质剂对硼铬系合金铸铁磨球进行变质处理后，使用了图象分析、Ｘ光分析技术研究了变质处理对磨球碳化物形态、类型及分布等的影响；装机应用表明，这种经变质处理的磨球耐磨性可显著提高（１０～３０％）。     

低锰球墨铸铁磨球材质的研究

研究了一种新型磨球材质－低锰球墨铸铁，并提出了该材质作为磨球使用的适宜组织。装机试验结果表明，该材质制成的磨球具有良好的抗磨性能．     

聚合物淬火介质SST301对斜轧半钢磨球硬度及开裂性的影响

研究了斜轧半钢磨球在淬火介质SST301中淬火后的硬度，淬裂敏感性，结果表明：适合斜轧半钢磨球淬火介质SST301的浓度应在1．0％－1．5％之间，且温度低于40℃。     

空冷贝氏体钢磨球和衬板

贝氏体磨球具有高的整体硬度，Φ１１０ｍｍ的磨球表面硬度ＨＲＣ，心部硬度ＨＲＣ，金相组织为均匀细小的贝氏体，回火氏体，碳化物和少量残留奥氏体。无缺口冲击韧工ａＫ＝（５００－８００）ｋＪ／ｍ＾２。贝氏体钢磨球磨耗为（５０－７０）ｇ／ｔ。水泥；破碎率为０－１．０％；失圆尺寸在球径技术标准误差范围内。     

凝固特性对低铬白口铸铁磨球组织,性能的影响

通过对砂型铸造和金属型铸造磨球在固特性的定量分析研究表明：砂型铸造磨球是典型的体积凝固，组织中存在着裂纹源－缩孔、缩松、缩气孔是磨球破碎率偏高、易于磨损的重要原因之一。而金属型铸适磨球接近逐层凝固，组织致密、磨耗低、不易破碎。     

RCM铸态中锰抗磨球铁磨球的强韧化研究

检测了一种改进型ＲＣＭ铸态中锰球铁磨球的组织和性能，提出了材质强韧化的措施，生产试验表明：采用Ｃｕ－Ｃｒ微量合金化并配合随流孕育变质处理，磨球的洛氏硬度保持在ＨＲＣ４５－５５，而冲击韧性可高达αＫ１０－２０Ｊ／ｃｍ＾２，成功地解决了此类合金韧性不足易破碎的问题。     

高炉－工频炉双联熔炼生产马氏体、抗磨球墨铸铁磨球的研究

介绍了利用高炉－工频炉双联熔炼铁水获得马氏体球墨铸铁磨球的生产试验方法：高炉铁水预处理及化学成分的确定，球化与孕育处理，球化剂加入量对球化效果的影响。还介绍了马氏体球铁磨球的热处理工艺。这种不含贵重合金元素的磨球同样具有良好的冲击疲劳抗力与磨料磨损抗力，生产成本低，经济效益高，社会效益好。     

奥－贝合金球铁磨球的研制与应用

奥－贝合金球铁磨球的研制与应用山东省宁津县磨球厂（２５３４００）刘汉生ＳｔｕｄｙａｎｄＡｐｐｌｉｃａｔｉｏｎｏｆＡｕｓｔｅｎｉｔｅ－ｂａｉｎｉｔｅＭｉｌｌｉｎｇＢａｌｌＬｉｕＨａｎｓｈｅｎｇ（ＳｈａｎｄｏｎｇＮｉｅｊｉｎＭｉｌｌａｌｌＰｌａｎｔ）在磨...     

消失模铸造低碳球铁磨球的工业生产

用所介绍的消失模工艺铸造低碳球铁磨球，在工业条件下可获得准铸态贝氏体组织磨球。通过在水泥厂应用，结果表明：磨球的成本可比低铬合金铸铁磨球降低18％，磨球的吨水泥磨耗降低80％，破球率降低一半。     

球磨过程中的碰撞行为分析

本文通过对行星球磨过程的分析，研究了行星球磨过程中的磨球碰撞行为，建立了球磨工艺参数与磨球运动速度。平均自由程及碰撞频率的理论关系。结果表明：随球磨转速提高，磨球运动速度和碰撞频率将增大，装料量一定时，提高球料比，磨球运动速率和平均自由程都将减小，碰撞频率增大，装料量和球料比一定时，磨球半径愈小，磨球运动的平均自由程减减小，碰撞频率增大。     

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。