高强度高韧性铸态球铁的生产

0引言在对球铁的研究中，一般认为高强度球铁应具有珠光体基体，而铁索体基体的球铁只具有高韧性的特点。经反复试验，本厂生产的铸态铁素体基体球铁同时具有高强度和高韧性的特点。1稳定原材料生产铸态球铁，原材料是基础。材料的质量对稳定生产铸态球铁至关重要，必须严格检查验收，并尽可能稳定供货厂家。1．1原生铁生产铸态球铁要求原生铁一高四低（即高碳、低硅、低锰、低磷、低硫），而且还要求含硫量稳定。因为铁液的含硫量直接关系到球化剂的消耗量，从而影响球化效果，影响球铁质量。本厂使用林县合合钢铁厂的214生铁，其化学成分…     

钢铁生产流程铁资源效率与工序铁资源效率关系的分析

以钢铁生产流程铁流图为基础，推导了实际钢铁生产流程铁资源效率与工序铁资源效率的关系式．以某钢厂年均生产数据为例，分析了流程铁资源效率与工序铁资源效率的关系，并讨论了工序铁资源效率对流程铁资源效率的影响．     

中硅耐热蠕墨铸铁的研究及应用

适当提高硅含量可有效地提高蠕铁的力学性能，抗氧化性能和热疲劳性能。中硅耐热蠕铁的高温强度比普通蠕铁提高３０％，与中硅球铁相当，抗氧化性能比普通蠕铁提高５倍以上，接近球铁远优于灰铁。在急冷条件下，热疲劳性能优于球铁和灰铁，随球化率下降，热疲劳性能提高。使用证明，中硅耐热蠕墨铸铁综合性能良好。适用于７００～８５０℃条件下工作的新型耐热材料     

难选贫铁矿煤基直接还原过程中固相反应特征

贫铁矿煤基直接还原过程中，贫铁矿中的铁氧化物除被还原成金属铁外，还有相当数量的铁氧化物同硅酸卤矿物发生固相反应，生成铁橄榄石和铁尖晶石类化合物。结果表明：在还原过程中存在碱性氧化物效应，即碱性氧化物从铁橄榄石和铁尖晶石中置换出ＦｅＯ，使得贫铁矿的还原条件大为改善。     

双联熔炼中铁液转运系统的改进

中国一拖集团有限公司第一铸铁厂熔化工部采用一台12t／h冲天炉和二台容量为10t的电炉双联熔炼。铁液由冲天炉向电炉转运时，使用1t的铁液包，通过炉前电动跑车与叉车将铁液包运至电炉前，使用电炉上方的10t吊车配合人力转动铁液包将铁液倒入电炉内。每次只有1t铁液运至电炉；若电炉内留底铁液为2～3t，那么至少要转运七八次铁液才能将一台电炉灌满。铁液在转运过程中温度降幅大，     

提高6110车用柴油机球铁曲轴的疲劳性能

由球铁拉伸性能和疲劳试验结果可见，球铁通过合金化可大幅度提高抗拉强度，但疲劳强度提高不多，而通过二次孕育处理可在提高球铁抗拉强度的同时，提高球铁疲劳强度。     

水附着对球墨铸铁拉抻性能的影响

研究了水附着对不同基体组织球铁的拉伸性能的影响，结果表明，水附着拉伸试验中，奥贝球铁、球光体球铁、淬火回火球铁的拉伸强度和伸长率同时下降，发生显著的水脆化；而铁素体球铁几乎无水脆化现象，这种水脆化现象是在超过屈服点的塑性变形中球铁表面附着水分解的氢的氢脆而导致的。     

汽车蠕墨铸铁件的应用与发展

东风汽车公司铸造一厂于1979年开始研究蠕墨铸铁，并于1984年开始用蠕铁大批量生产卡车排气管，解决因热疲劳强度低容易开裂损坏问题。上世纪90年代初，又开始生产轿车蠕铁变速箱壳体和排气管。25年来生产各种蠕铁近400万件，质量约在40 000t左右。蠕铁扩大应用目前还面临一些问题，铸造业要尽快完善蠕铁标准，提高管理水平和工序控制能力，掌握稳定生产蠕铁的技术。     

高韧性等温淬火球铁力学性能的研究

根据欧洲等淬球铁标准EN1564的数据，建立各力学性能之间的数学模型。对高韧性等淬球铁铸件的生产检测结果进行了分析，发现合金化的高韧性等淬球铁铸件的力学性能之间的关系与一般非合金化等淬球铁铸件不同，其伸长率、冲击韧度、屈服强度、硬度在一定范围内随抗拉强度的提高改变不大。生产实践证明：设计合理的化学成分，经过适当的合金化，铸造优质的球铁毛坯，采用有效的热处理工艺，可大幅度提高等淬球铁的综合力学性能，稳定生产高韧性等淬球铁铸件。     

等温淬火球墨铸铁的滑动磨损

研究了奥贝球铁，下贝球铁及与其基体组织相同的钢的滑动磨损性能。实验结果表明：在一定条件下，石墨对等温淬火球铁耐磨尾无补而有损，由于奥贝球铁的转折载荷随摩擦速度的提高而增大，当转速为９８０ｒ／ｍｉｎ，载荷〉６８．６Ｎ，等温淬火球铁的耐磨性优于钢。     

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。