高铬铸铁磨球在氧化铝生产中的应用

高铬铸铁磨球在氧化铝生产中试验使用结果表明，该磨球耐磨性强，碎球率低，球耗量少，是目前磨机较理想的磨矿介质。高铬铸铁磨球取代球耗高的４５＃锻钢磨球，是降低磨矿成本途径之一。     

低碳球墨铸铁冲击磨料磨损特性的研究

研究经准铸态贝氏体工艺处理低碳球墨铸铁冲击磨料磨损特性。采用消失模铸造工艺，经准铸态贝氏体工艺处理后，得到了贝氏体组织。冲击磨料磨损过程以冲击变形磨损为主，兼有切削磨损和凿削磨损。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％，而磨球的吨水泥磨耗还不到后者的80％，破球率降低了50％。     

多元低合金贝氏体铸钢磨球的研究

针对常用磨球材质脆性大、耐磨性低、磨耗高的缺点，研制了多元低合金贝氏体铸钢磨球，它具有硬度高、硬度均匀性好和韧性高等特点，用于磨矿生产，磨耗接受高铬铸铁球，成本降低３０％～４０％，综合效益显著。     

消失模铸造低碳球铁磨球的工业生产

本文介绍的消失模铸造低碳球铁磨球的生产工艺过程,在工业条件下可获的准铸态贝氏体组织,并对磨球进行了试验测试.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%,但磨球的吨水泥磨耗降低了80%,破球率降低了一倍.     

湿型生产高韧性高铬铸铁磨球

通过合理的设计浇冒口系统和磨球成分，改进热处理工艺，使湿型生产高铬磨球的工艺出品率达６８～７０％，成品率≥９８％，吨水泥球耗低于４０ｇ，破碎率小于０．１％。     

铬锰钨抗磨铸铁磨球在氧化铝生产中的应用

通过铬锰钨抗磨铸铁磨球在氧化铝原料磨生产中的试验,表明该磨球具有耐磨性强,碎球率低,球耗量低的优点,是目前原料磨较为理想的研磨介质.用铬锰钨抗磨铸铁磨球取代现用合金一号磨球,可以有效降低生料浆的生产成本,并提高原料磨的产能和连续运转时间,降低职工劳动强度.     

铁型覆砂铸造磨球工艺的试验研究

应用铁型覆砂铸造技术和计算机仿真技术，研究了铁型覆砂铸造磨球工艺的原理，按照生产线标准研制了铁型覆砂铸造贝氏体球铁磨球工艺装备和试验装置，进行了现场工艺试验，获得了关键工艺参数数据。试验结果表明，新工艺生产的磨球尺寸精度可以达到CT6级，表面粗糙度达到Ra12．5，球铁材质铸态硬度（HRC）平均值为32～34，直径60mm磨球的工艺出品率达到70％，生产工序少、周期短，适合机械化生产线方式进行大规模生产。     

利用钨渣复合合金化生产低铬磨球

利用钨渣铁合金中的Ｗ、Ｎｂ、Ｔａ、Ｔｉ等强化低铬合金磨球组织，提高耐磨性；采用金属型铸球并利用铸造余热进行淬火，提高了磨球硬度、强度和韧性，同时降低了生产成本。     

球磨机磨球的服役条件及工艺设计

对球磨机中磨球的工作情况、受力情况及失效形式进行了分析研究。为克服磨球在使用过程中性脆、耐磨性不好的缺陷，根据金属型球铁磨球非平衡凝固特性．提出了金属型球铁磨球的工艺设计方案。     

用低合金贝氏体球铁制造磨球

庚球材质要求高的疲劳强度，硬度和高的冲击韧性。寻求一种质量稳定，能够取代高铝铸铁磨球，又要立足国内资源，制造成本低，利于推广的管磨机用磨球，是我们研究的目的。1低合全贝氏体球铁鹰球的特点与化学成分设计低合金贝氏体球铁磨球生产成本低：3000～5000元／吨；合金含量少，且均为常用合金元素；综合性能好，50～60HRC，ah＞15）／cm‘；破碎率低；应用范围广；是高铝铸铁磨球及其它铸铁磨球无法比拟的，经济效益也好于其它材质磨球。根据我们研制生产及应用实验的结果对低合金贝氏体球铁磨球的化学成分，设计如表1。表1低合金贝…     

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).     

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.     

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.     

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。