一九八九年度《重型机械》总目录

题目沁_生一题目期页序号 冶炼工艺与设备{现代弧形连铸机的多点矫直和}连续矫直}宝钢450m2烧结机的安装与调整(啄坯连铸机辊列参数的优化设…计顾0300In,板坯连铸机拉矫辊机{械应力分析{电加热密排辊连续退火炉焕辊}机的研讨!”吨电弧炉的改造}节能炼钢炉1新型板坯连铸机1英国     

新型的板坯连铸机辊列布置

通过对国内某钢铁企业提供的板坯连铸机辊列参数以及结晶器内周期性液面波动的生产数据进行分析,探讨了采用细辊密布形式和差异性的辊径、辊间距及5次方曲线设计的连续弯曲和连续矫直板坯连铸机辊列后,不仅使连续弯曲和连续矫直的整个过程曲率均匀变化,而且形成弯曲线与圆弧线、圆弧线与矫直线、矫直线与水平线等曲率光滑对接,基本上避免了结晶器内周期性液面波动的发生。     

板坯连铸机的辊列设计计算与分析

连铸机的辊列设计是整个连铸机设计的核心内容。论述了基于连续弯曲和矫直的板坯连铸机辊列布置的计算方法和过程,包括铸机外弧轨迹线的确定计算、辊径的选择计算、内外弧辊心位置坐标的计算、内弧辊间间隙和段间更换间隙的计算等。在通过与外商的辊列数据对比后认为,论述的计算方法是可靠的。     

中冶赛迪板坯连铸技术的发展现状

介绍了中冶赛迪工程技术股份有限公司近几年来在板坯连铸机领域所取得的技术进步,并着重描述了CISDI板坯连铸机的几项关键组成技术,包括多功能大容量钢液罐回转台、大容量带控流装置中间罐、结晶器液压振动成套技术、动态二冷喷淋控制技术、板坯轻压下成套技术、连续弯曲连续矫直辊列技术、基于传热机理模型的二冷系统设计技术和板坯质量诊断分析系统.     

首钢二炼钢厂板坯连铸机弯曲段与矫直段的改造

介绍首钢二炼钢厂板坯铸机改造的概况，阐述单点矫直、康卡斯特连续矫直和连续矫直修正曲线的特点。优化设计多点连续弯曲和矫直辊列，实现光滑连接，更有利于保证铸坯质量。     

直弧形板坯连铸机辊列设计的优化方法

针对常规直弧形板坯连铸机的辊列设计,介绍了铸机主半径、弯曲段长度、矫直段长度与铸机高度之间的关系,提出了辊列参数的优化方法,并对优化前后铸机的受力情况进行了简要分析。对于直弧形板坯连铸机,在铸机长度以及垂直段高度确定之后,铸机主半径及弯曲段长度的取值范围主要取决于铸机的高度;根据铸机的高度,主半径及弯曲段长度可以计算出铸机的矫直段长度。利用计算机对辊列参数进行优化后发现在减小铸机主半径的同时增加弯曲段和矫直段的长度可以在一定程度上减小铸坯受到的鼓肚力并降低浇注过程中的拉坯阻力。     

板坯连铸机辊列参数的优化设计

本文推导出板坯连铸机铸坯的变形公式,建立了辊列优化设计的数学模型,并以某厂板坯连铸机为实例进行计算,使辊列参数得到了优化,为板坯连铸机的辊列优化设计提供了新途径。     

基于泰勒级数的连续矫直在实践中应用

现有采用多点矫直技术的连铸机一般矫直段较长,不满足矫直段长度远小于基本弧半径的前提条件,无法用康卡斯特矫直曲线实现连续矫直改造。在连铸机改造项目设计实践中运用泰勒级数方程计算连续矫直曲线,避免了康卡斯特方程带来的改造难题,有效实现了连铸机的连续矫直。     

直弧形连铸机辊列设计中基本概念的最新阐述

通过多点弯矫或连续弯矫概念的阐述,就现代化板坯连铸机多点弯矫或连续弯矫时辊列设计中的有关概念进行了澄清,特别就按照辊列新的设计方法设计连续弯矫时三次方曲线怎样和圆弧衔接方面作了大量实际工作和深入的研究,为板坯连铸辊列设计研究提供了新思路。     

连铸机中连续弯矫曲线求解

上个世纪70年代国外某公司在连铸机中引入了渐近弯矫的理念,80年代康卡斯特最早提出连续矫直的概念,即利用特定曲线设计辊列,本文就这一特定曲线进行求解,给出了表达式并与引进的连铸机辊列曲线进行了对比,结果比较吻合。     

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.     

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.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.