电磁铸造液柱高度数学模型的建立及应用

为了研究熔体金属电磁立柱成形能力并计算电磁作用下的液注高度,从电磁铸造立柱成形的基本原理出发,建立了电磁场作用下金属立柱成形时液柱高度数学模型,并试验验证了模型的准确性.利用液柱高度数学模型对铝、钢、锡铅合金等金属的电磁铸造可行性,以及电力参数对液柱高度的影响进行研究.结果表明:铝电磁无模成形能力最强,而钢及锡铅合金电磁无模成形能力则基本相同;钢及锡铅合金电磁立柱成形所需的磁感强度约为0.08～0.10 T,而铝则只需约0.04T.     

稀土Pr对Al2O3-SiO2(Sf)/ZL109复合材料组织及性能的影响

本文采用挤压浸渗法 ,制得不同稀土含量的硅酸铝短纤维增强铝基复合材料。用光学显微镜观察了复合材料的铸造显微组织 ,分析了稀土含量对共晶硅组织形态的影响 ;用扫描电镜对复合材料基体中的稀土相进行了观察 ,探索了稀土相的分布位置及其形态 ;并对不同稀土含量的复合材料进行了摩擦磨损实验 ,结果表明稀土能增强复合材料的耐磨性     

离心浇铸法制备光谱控制样的分析研究

本文研究了应用高频熔化、冶炼、离心浇铸成型新技术,制备光谱控制样的方法及可行性,研究证明,利用本方法制备出的光谱控制样表面光洁度高,均匀性好,且组织结构和基体成份与分析试样一致,可用于光谱分析中工作曲线的校准和质量控制.     

Rendering of Surface and Volume Details in Volume Data*

Aiming at the detail rendering in volume data, a new volume illumination model, called Composed Scattering Model (CSM), is presented. In order to enhance different details in volume data, scattering intensity is decomposed into volume scattering intensity and surface scattering intensity with different weight functions. According to the Gauss probability distribution of gray and gradient of data, we propose an accurate method to detect the materials in a voxel, called composed segmentation. In addition, we discuss the principle of constructing these weight functions based on the operators defined in composed segmentation. CSM can generate images containing more details than most popular volume rendering models. This model has been applied to the direct volume rendering of 3D data sets obtained by CT and MRI. The resultant images show not only rich details but also clear boundary surfaces. CSM is demonstrated as an accurate volume rendering model suited for detail enhancement in volume data sets.     

小方坯连铸机的PLC自动控制

本文对弧型小方坯连铸机工艺与设备进行了分析，介绍了连铸生产的ＰＬＣ控制系统。及其软件设计。     

铅黄铜水平连铸棒材熔铸工艺的试验研究

在工业生产条件下，对影响HPb59－1水平连铸律材热轧开裂的熔铸工艺进行了试验研究．取三个熔铸工艺因素：铸造速度、冷却水压力、冷却水温度．试验结果表明；铸造速度对热轧开裂影响极为显著，使其控制在410mm／min左右可获得较为理想的效果．     

真空熔炼高压气体雾化制粉技术及设备

介绍了气体雾化粉的品种、用途及工业化生产。还介绍了真空熔炼-高压气体雾化制粉所需的设备。     

浅谈青钢“九五”发展思路

青钢应从我国钢铁工业的实际出发，在“九五”期间，遵循量力而行的原则，采取两步走的方法，于１９９８上和２０００年分别达到年产８３万ｔ和１１７万ｔ钢的综合生产能力。主要措施是：优化工艺结构，消除二次化铁炼钢；优化炼铁系统装备结构；推进炼钢技术进步，提高连铸比，并以市场为导向，优化产品结构。     

Hydrothermal Synthesis of Acicular Lead Titanate Fine Powders

A pure, acicular lead titanate (PbTiO₃) fine powder with a white color has been prepared by hydrothermal synthesis. It is a new phase of PbTiO₃ with I 4 symmetry, cell parameters of a = 12.358 Å and b = 14.541 Å, and a density of 6.80 g.cm⁻³. The influences of pH (12.5 to 14.4), Pb/Ti ratio (1.0 to 1.6) in the feedstock, reaction temperature (130° to 230°C), time (0.25 to 4 h), starting materials, and additives on the formation of acicular PbTiO₃ under hydrothermal conditions have been investigated. The acicular PbTiO₃ with I 4 symmetry, referred to as the PX phase, can be converted to the perovskite-type (PE phase) of PbTiO₃ at about 605°C while its acicular morphology is essentially unchanged. The preferable conditions for preparing pure acicular PX-phase PbTiO₃ are that the pH is 13.0 to 14.0, Pb/Ti ratio is >1.3, reaction temperature is 170° to 200°C, time is 0.5 to 1.0 h, titanium butoxide (Ti[O(CH₂)₃CH₃]₄) is the starting material, and poly(vinyl alcohol) is an additive. The acicular grain of the PX phase is usually less than 100 nm in diameter and more than 1000 nm in length.     

Mg-Li-Al合金近液相线制浆及部分重熔

采用近液相线铸造方法制备了Mg—5％Li—3％A1合金的半固态浆料。通过对该合金近液相线铸造与常规铸造组织进行比较，以及在不同静置时间、不同冷却速率下对其铸造组织的影响，较详细地分析了近液相线铸造组织的变化过程。试验结果表明，在Mg—Li合金熔炼中，添加2％Ca可实现阻燃，但效果不如对一般镁合金；与常规铸造相比，近液相线铸造可获得均匀、细小枝晶的组织结构；适当静置或提高冷却速率有利于组织的细化和均匀化；在适当的部分重熔工艺条件下，坯料组织可获得较理想的触变组织。