本钢7号高炉操作制度的改进

7号高炉适时调整操作制度,优化高炉操作,采取"大α角、大矿角"布料,通过稳定焦炭平台、中心加焦保证了中心气流的发展,实现大批重生产,提高了煤气利用和冶炼强度,降低了燃料比,实现了节耗、增产的目的。     

焦炭质量对高炉炼铁的影响

介绍焦炭在高炉炼铁过程中所起的作用。总结了近年来高炉炼铁对焦炭质量的需求趋势,分析近年来关于焦炭质量对高炉炼铁影响的不同学术观点。阐述了关于焦炭质量对高炉炼铁影响的最新研究成果。对提高焦炭质量、降低炼铁生产成本提出了建议。     

使用小块型焦有利高炉顺行

一般焦炭粒度不均匀，装入高炉后，大块焦炭向高炉中心滚动，小块焦炭堆积在高炉边缘。到达直接还原区后，由于与CO2发生溶损反应，焦的组织脆化、强度降低，产生多量粉末，使高炉内造气性变差，特别是高炉边缘小块焦粒度小时，对高炉颁行极为不利。新日铁公司在一般焦炭中配用小块型焦（粒度＜30mm），并且使这部分小块型焦装入高炉边缘，解决由于溶损反应引起的粉焦堆积问题。把煤粉压制成形、进行干馏得到的型焦，与CO2发生反应的开始温度为900℃，而一股焦炭与CO2发生反应的开始温度为1000－1100℃，因此如果把型焦和一般焦炭同时装…     

焦炭质量对大喷煤高炉冶炼过程的影响

分析了酒钢1号高炉在2005～2006年的生产实践数据;研究了焦炭质量对大喷煤高炉冶炼过程的影响;有效评定了焦炭的质量指标;并在确保高炉优化用料的同时,提出了合理使用焦煤资源的有益建议。     

宝钢信息三则

1宝钢1994年铁钢生产任务提前完成宝钢炼铁厂于1994－12－25提前完成全年产铁680万t的生产任务，铁水一级品率达到95．5％。上半年由于原料原因造成高炉炉况不顺，曾一度欠产；下半年该厂合理调整了原料配比，提高焦炭和烧结矿质量，加上高炉职工精心操作、设备人员认真点检维护，确保炉况稳定颁行，逐渐把产量追上。3号高炉投产后，1、3号高炉搭接生产，由于3号高炉产量稳步上升，为全年生产任务的完成创造了条件。宝钢炼钢厂于1994．12－23提前完成全年产钢730万tfe｛IFE产任务，累计生产了钢水732．4万t，折合钢锭、钢坯706万t，质量、…     

长钢焦炭性能对高炉冶炼的影响

高炉炼铁近年来生产指标不断改善,但能源的短缺也给高炉带来了新的挑战,于是降低焦比,提高喷煤比成为降低生铁成本的有效手段之一,也成为高炉炼铁系统优化的重要环节。而降低焦比,提高喷煤比的有效措施之一就是提高焦炭质量,特别是焦炭的热态性能指标。     

用高炉铁水直接铸造钢锭模

本文概述了用高炉铁水直接铸造钢锭模的工艺技术。这种钢锭模与冲天炉熔制的相比较,每吨产品成本的降低约9.5％,寿命提高10％以上,由于使用炼钢铁水,故可使高炉增产10～15％,节约焦炭40公斤。经济效益显著,全年可节约500万元以上。     

氧化铝赤泥在黑色冶金烧结料中的使用效果

目前,氧化铝生产的废料赤泥仍弃之堆场。赤泥中含有较多的铁和少量二氧化硅,因此有可能用于高炉熔炼。然而,用赤泥代替富铁精矿(SiO_2为4～7,Fe为60～65％时)会增加出渣量和消耗过量焦炭,如果这些损失不能为提高烧结料的强度所弥补的话,甚至还会降低高炉熔炼效率。     

碱金属盐对本钢焦炭热性能影响浅析

为了更好地使高炉生产顺行,维持炉料良好透气性显得尤为重要,这就要求焦炭在反应时热态性能稳定良好。一方面要提升入炉前焦炭热态性能,另一方面高炉内碱金属富集对焦炭的劣化影响也越来越受到重视,有必要加以研究和改善。文章通过采用在碱金属盐(碳酸钠和碳酸钾)溶液中浸渍焦炭来增加碱金属含量的方法,分析了碱金属含量变化对本钢焦炭热性能的影响程度及趋势,为研究焦炭在高炉内的行为提供参考依据。实验结果表明,碱金属盐对焦炭熔损反应起到正催化作用,其中钾盐的催化作用要强于钠盐,破坏作用更大,需要对炉料中碱金属含量特别是钾含量引起足够重视并加以控制。     

本钢七号高炉大矿批的研究及应用

七号高炉采取大α角、大矿角布料,在稳定焦批创造稳定的焦炭平台的同时,通过中心加焦保证了中心气流的发展,实行大矿批生产,提高了煤气利用,提高了冶炼强度,降低了燃料比。目前七号高炉的利用系数达到了2.350t/(m3·d),焦比降低到340kg/t,燃料比降低到523kg/t,同时减少设备损耗,降低设备休风率,实现了大矿批生产节耗、增产的目标。     

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。