不同碱度的烧结矿试验研究

唐钢炼铁厂北区新建180m2烧结机投产后,为了解烧结矿碱度的降低对烧结矿产质量的影响程度,对同一原料条件、不同碱度水平的烧结进行试验室研究。结果表明,在唐钢炼铁厂现有原料条件下,随着烧结矿碱度的降低,烧结矿质量呈下降趋势。新建180m2烧结机投产后,烧结矿的碱度应控制在1.85以上。     

西德Ilsede冶金公司GroβIlsede炼铁厂的新型烧结设备

该厂为了在提高经济性的同时提高生铁产量,决定于1965年起采用100%的自熔性烧结矿作为高炉炉料。由于原来的75米~2的带式烧结机已不能满足每天生产6000吨烧结矿的需要,故要采用较大的烧结机,因为大型烧结机的购置费、生产维修费、耗电费都比几台小型烧结机的低(按每生产一吨烧结矿计),而且大     

邯钢烧结机扩容改造实践

通过对邯钢新区2台360 m2烧结机的扩容改造取得了烧结机产量、性能的提升。新技术的引进实现了主要设备改造的目的,为其他同类型烧结机的扩容提供了借鉴。     

本钢360m^2烧结机工序优化研究及生产实践

介绍了本钢三烧车间360m^2烧结机的重点工艺技术及工艺优化、技术改造、操作情况,分析目前烧结矿主要技术经济指标状况,并指出当前烧结存在的问题及发展方向。     

浅议安钢烧结发展和技术进步

通过安钢股份公司烧结厂的烧结矿产量、烧结机机型、烧结矿指标的变化,对安钢烧结行业的发展进行了大致描述,对安钢烧结生产的技术进步进行了简要介绍,指出了安钢烧结矿产品质量的不断提高和烧结设备大型化是近年来安钢烧结产业发展的主要特征。     

比利时Cockerill公司Ougree厂的烧结车间

1976年5月18日在比利时 Cockerill 公司 Ougree 厂投产的 DL 5型烧结机是 De-latte—Levivier 公司在比利时制造的第二台机上冷却烧结机。第三台建于卡罗莱附近的 Forges de Thy Marcinelle 公司,于1977年11月投产。机上冷却的烧结法的特点是:烧成后的烧结矿不经破碎可以迅速而均匀地冷却,可以得到没有过多大块矿的块度均匀的烧结矿,而且卸料端无过多的粉矿。这种类型的烧结机还可以减少维修费用和降低烧结矿成本。     

MEBIOS技术的工业化应用现状

介绍了新日铁住金开发的RF-MEBIOS技术及其提高烧结机利用系数的工业化应用效果。也介绍了新日铁住金借助MEBISO技术大大提高了巴西超细精矿粉的烧结配比,同时烧结机利用系数得以提高、燃耗得以降低。新日铁住金和JFE最近都针对MEBIOS技术而开发了提高生球团强度的技术,如果把这些技术应用于实际生产,将进一步提高烧结料层透气性,达到提高烧结矿生产率和改善烧结矿冶金性能的目的。     

赤热烧结矿覆盖在烧结料层表面的烧结方法

日本川崎公司水岛厂发明了一种把赤热烧结矿（≥1000℃）覆盖在烧结料层表面的烧结方法。该方法是将烧结台车上烧成的烧结矿，通过机尾烧结矿破碎机和振动筛把筛下的（＜150mm）赤热烧结矿，用料斗运送到烧结机头部，覆盖在准备好的烧结料层表面，此时烧结料不必再进行点火，赤热烧结矿的高温热就能起到点火作用，然后靠抽风机使空气从上向下通过赤热烧结矿层和烧结料层进行烧结。这种烧结方法有下述优点：①点火用燃料大幅度降低，因为用点火器对烧结料层点火，仅在烧结机生产起动时。一旦有赤热烧结矿产生，就不需要对烧结料层进行点火；…     

配加高品位印度粉矿的烧结试验

用印度粉矿替代澳大利亚粉矿,烧结机利用系数降低,烧结矿强度下降,返矿率上升,影响了烧结生产的技术经济指标。为此进行了在现有原料条件下配加高品位印度矿的烧结试验。实验室试验结果表明,用8%高品位印度粉矿替代8%澳大利亚粉矿,钢渣配比由4%增加到6%,烧结矿中<5mm的粉末含量下降,烧结机利用系数、转鼓指数均有较大的提高。     

水钢4^#，5^#烧结机工程的设计特点

水钢4#,5#烧结机工程具有当今国内先进水平的工艺技术和装备.采用了计算机自动称量配料、返矿配料工艺,强化混合造粒功能的二次混料工艺,高负压、大风量、铺底料和厚料层的烧结技术,烧结矿热破碎后不经热振筛,直接进入环冷机冷却,冷烧结矿不经冷破碎,直接进入两段筛分的整粒工艺流程,生产过程采用了先进的自动检测和自动控制系统.笔者从设计的角度,阐述了水钢烧结机工程的设计特点,可供类似工程借鉴、参考.     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.