双辊薄带连铸技术的研究现状及进展

综述了国内外双辊薄带连铸技术的研究概况，指出了这种先进技术在工业化应用中存在的问题，并展示了它今后的发展方向。     

A New Analytical Model for the Flow Stress of Twin-roll Casting Magnesium Sheet at Elevated Temperatures

To evaluate the flow stress of the twin-roll casting magnesium sheet in high temperature forming processes,a new analytical model was proposed by analyzing stress-strain curves measured under various temperatures and strain rates.The model can be parameterized to reflect the volume fraction of semi-sold grain and sold grains undergoing twinning.By applying the new model,the result showed that the simulated stress-strain curves fit the experiment data very well.Such curve fitting can be employed for any magn...     

双辊薄钢带-铸辊界面热流特征的研究进展

综述了双辊薄钢带连铸过程中薄带-铸辊界面热流特征的研究进展.重点阐述了薄带-铸辊界面热流特征的研究方法及其所取得的成果,总结了界面平均热流系数的取值,并分析了界面热流与薄带凝固组织的关系.     

Microstructure and Eutectic Carbide Morphology of the High Speed Steel Strips Produced by Twin Roll Strip Casting Process

The M2 high-speed steel strip was produced by using the laboratory scale twin roll strip caster. The microstructure and eutectic carbide morphology of thus produced products were observed and analyzed, and the comparison of those with conventional products was carried out. The effects of the processing parameters such as the melting temperature, the pouring temperature, rolling speed and separating force on the microstructure and eutectic carbide morphology and their distribution were analyzed. The spheroidizing process of the strips in the annealing process was investigated. The relations between the growth and spheroidizing of the eutectic carbide and the annealing technology were obtained, and the mechanism of the twin roll strip casting process improving the eutectic carbide spheroidizing was discussed. The theoretical instruction for determining the subsequent treatment process was provided.     

反向凝固连铸薄带技术及其若干基本问题探讨

简述了反向凝固薄带连铸技术的工艺原理,阐述了反向凝固技术的特点、竞争力,介绍了其研究现状,论了反向凝固技术所涉及的若干基本问题。     

薄带连铸含磷低碳钢的组织性能研究

介绍了国内外在薄带连铸含磷低碳钢组织性能方面的研究进展.双辊薄带连铸的生产方式在一定程度上能提高固溶在基体中的磷含量,减小钢中磷在晶界上的偏析,对力学特性没有负面影响.指出采用双辊薄带连铸工艺来尝试含高磷薄规格耐大气腐蚀钢种的开发是一个具有工业化应用前景的方向.     

Numerical Simulation of Stress and Deformation for a Duplex Stainless Steel Impeller during Casting and Heat Treatment Processes

A large-scale, thin wall duplex stainless steel impeller with complex geometry was deformed severely and unpredictably during casting and heat treatment processes resulted in dimensional failure for the final part. In this paper, the distortion of the impeller during casting and heat treatment was calculated. A commercial software, Experto-ViewCast, was used to simulate the transient heat transfer, solidification and mechanical behaviors during the casting and the heat treatment process. The coupled set of governing differential equations for mass, energy and mechanical balance were solved by finite control volume and finite element method. A thermoelastic-visco-plastic rheological model was used to compute the constrained shrinkage of the casting. At each time increment, a coupling of the heat transfer and mechanics was performed. Comparison of the experimental measurements with the model predictions showed good agreement. From the calculated displacements of key points of the blade, the proper inverse displacements were determined to provide an optimum casting pattern and to achieve a uniform and reasonable machining allowance for both faces of the blade.     

Simulation Using Realistic Spray Cooling for the Continuous Casting of Multi—component Steel

A three-dimensional heat transfer model for continuous steel slab casting has been developed with realistic spray cooling patterns and a coupled microsegregation solidification model that calculates the solidification path for multi-component steels.Temperature and composition dependent properties are implemented in a database for 15 chemical species.Considerable effort is made to accurately model the spray cooling heat transfer.Each spray nozzle position and distribution is considered, including variations of the spray patterns with flow rate, and spray overlay .Nozzle type, layout, nozzle-to-slab distance, and spray span and flux are variable.Natural convection,thermal radiation and contact cooling of individual rolls are computed. The present model provides more comprehensive information and realistic slab surface temperatures than results from a model using the “averaged“ treatment of boundary comditions .Cooling operating conditions and parameters of individual spray nozzles can be analzed to optimize muzzle spray distribution ,improve product quality,and troubleshoot issues such as nozzle clogging that may arise during production.One spray cooling correlation is used for the entire machine,achieving as good or better agreement with surface temperatre measurements than was found previously for the model using an “averaged“ treatment of boundary conditions and using three machine-segment-dependent correlations.     

国内不锈钢焊带的研究现状

根据焊带的分类,分别介绍了奥氏体、马氏体、双相不锈钢、镍基焊带及其研究现状,指出国产焊带的主要问题是品种单一及质量不稳定,与工业发达国家仍有一些差距.对我国焊带的发展进行了展望,即应适当改进熔炼加工工艺,加强对现有焊带质量的提高、控制,研发高性能、高质量的新型焊带.     

铁素体不锈钢430连续铸造板坯成形合理工艺参数的研究

目的 以某钢厂板厚为180~220 mm的铁素体不锈钢430连铸板坯为对象,研究合理的板坯连铸工艺参数,以提高不锈钢430连铸坯的等轴晶率,强化铸坯质量。方法 通过高温拉伸试验、结晶器凝固冷却温度分析以及电磁搅拌磁感应强度模拟,探讨了液体加热温度、结晶器冷却水参数及电磁搅拌参数等工艺参数对连铸坯质量的影响规律。结果 高温拉伸试验结果表明,430不锈钢在不同温度下的应力-应变曲线都是典型的塑性拉伸曲线,当温度超过1 000 ℃后,抗拉强度显著减小;在结晶器宽面水量3 400 L/min、窄面水量400 L/min的参数条件下,结晶器宽面及窄面铜板温度均匀,满足铸坯成形要求;在扇形1段第6^#和7^#辊位并列增加电磁搅拌辊后,430不锈钢铸坯电磁场分布合理且铸坯中心磁感应强度最大,为0.104 T,平均磁感应强度为0.09 T,显著提升了液相穴内钢水的流动性。结论 在结晶器宽面水量为3 400 L/min、窄面水量为400 L/min条件下,在连铸机扇形1段第6^#和7^#辊位并列增加电磁搅拌辊后,对430不锈钢进行连续铸造工业试验,铁素体不锈钢430板坯等轴晶率达到62.5%,裂纹发生率降低。     

Optimization of Continuous Casting Using Simulation

This paper describes the development and use of an integrated system of metamodels and simulation experiments for managing quality in a continuous casting system. A systematic procedure was developed to satisfy the necessary process conditions connected to one or more process parameters. The values of these parameters are to be determined such that all the process conditions are satisfied simultaneously to ensure that the product will have the desired quality. This procedure utilizes a set of metamodels, simulation experiments, and an index called the “undesirability index” for quality, which establishes a functional relationship between the input variables or process parameters and the quality criteria. This system, when applied to the data pertaining to a case, demonstrated that the methodology developed could be used to effectively manage product quality.     

SUS304不锈钢汽车装饰条腐蚀原因分析

为查明某企业304不锈钢汽车装饰条发生锈蚀的原因,从材料材质、锈蚀点形貌、锈蚀发生位置成分等几个方面进行分析,同时采用盐雾加速腐蚀试验方法测试了材料耐腐蚀性能.结果表明,材料在酸洗后酸洗液未清洗干净,导致了材料表层发生腐蚀,打磨可以避免材料的进一步腐蚀.     

奥氏体铸造不锈钢刮刀杆

左右刮刀杆是涂刷设备中关键零件,材质为1．4308铸造不锈钢;零件主要由台阶空心圆柱体、异性方孔和悬臂支架组成。左右刮刀杆制造精度高、工艺性较差。在制造中,铸件使用硅溶胶精密铸造工艺,设计了通用组合夹具、冲模、专用检具和工装,解决了产品加工制造和检验测量的问题,保证了左右刮刀支架的制造精度。     

基于计算机模拟的支架铸钢件铸造工艺设计及优化

目的对ZG270-500铸钢支架的铸造工艺进行优化设计,以达到工艺简单、成本低、操作简便、质量良好等要求。方法使用三维CAD软件和铸造模拟软件对相应铸造工艺方案进行了三维建模和铸造过程的模拟。针对工艺初始浇注系统设计了正放、倒放,底注式、阶梯式共4种不同组合的浇注方案。在对充型温度场进行模拟后,选择了倒放阶梯式与正放底注式浇注系统进行后续模拟。在对凝固进行模拟后,最终选择了正放底注式的方案并进行后续优化。在设计补缩系统时,通过多次调整冒口的位置与尺寸,以及冷铁的位置、尺寸与形状,达到工艺优化的效果。结果 4种初始方案中,倒放阶梯式浇注系统有利于顺序凝固,正放底注式浇注系统较为经济环保。凝固过程中,正放底注式浇注系统的疏松疏孔液相孤立区存在于铸件顶部,有利于补缩。初始补缩系统有效补缩了顶面两孔中心缺陷,优化后可使顶板和肋板的连接处,凝固最晚区域的缺陷大为改善。结论模拟表明,最终方案可基本消除铸件中的缺陷,保证铸件的质量与良好的工艺性。     

Two Dimension Finite Element Simulations on the Electromagnetic Containment in Twin-Roll Strip Casting

Distribution of magnetic field and electromagnetic force in twin-roll casting of steels was studied by the metod of numerical simulation in this paper,Two-dimension finite element model ,which includes the regions of melt ,stainless collar ,coil and magnetic core ,has been constructed,By solving magnetic vector potential formulations of quasi-static electromagnetic field,distribution of magnetic flux density and magnetic force at different molten heigh is determined,Calculated results showed that intensity of the distribution of magnetic flux density increased linearly with the increased coil current ;and the magnetic force in the melt increased as a quadratic cure with creased coil current ,More attention was given to the distribution of eddy current and magnetic force in the melt ,the confine effect at different molten height was also discussed.     

铝合金连续铸轧数值模拟现状及研究展望

介绍了目前关于铝合金连续铸轧过程数值模拟方法的种类以及面临的突出问题,结合当前国内外研究的现状,展望了铝合金连续铸轧数值模拟的发展趋势。     

熔模精铸型壳预热转移过程温度场及换热规律研究

目的 为了获得不同工艺条件对高温合金熔模铸造型壳在预热及转移过程中温度分布的影响规律.方法 根据实际工况设计了测温实验方案,采用热电偶测温的方法研究型壳在无保温措施、外加保温棉、填砂以及保温棉复合填砂4种工艺条件下对型壳在预热及转移过程中温度分布的影响.获得了型壳升温、保温和转移过程中的温度场变化曲线,并根据实际测温曲...     

低频电磁场对奥氏体不锈钢铸坯组织的影响

在工业实验中研究了低频电磁场对水平连铸奥氏体不锈钢组织的影响,结果表明:在低频电磁场作用下,合适的电磁搅拌参数使奥氏体不锈钢宏观组织在一定程度上得到了明显改善,铸坯的柱状晶和等轴晶得到了显著的细化,消除了穿晶现象,等轴晶区扩大,中心缩孔、中心疏松级别明显降低;多次实验发现:对于奥氏体不锈钢,所需的搅拌强度应高于一般钢种,即使搅拌器的中心磁感应强度达900GS平均值(幅值达到1413GS),采用3～4Hz的频率,搅拌后对钢液的组织影响较小;在同样的磁场强度下,不锈钢液由于粘度大,因而其转速比碳钢液的转速约低20%～30%。     

平面流铸快速凝固过程的数值模拟研究进展

本文对平面流铸工艺快速凝固过程的数值模拟研究现状作了介绍。主要内容包括 :(1)对溶潭的形成及特征、平面流铸工艺参数对条带形成及质量的影响的数值模拟 (2 )结合快速凝固过程的形核和晶体生长的动力学特征对平面流铸凝固过程的数值模拟 (3)平面流铸过程界面传热系数的数值模拟。文章最后 ,提出了平面流铸工艺快速凝固数值模拟研究的进一步发展方向