V法铸造工艺、设备和质量

介绍了利用真空V法工艺生产铸铁件、铸钢件的实际应用过程,总结了V法造型工艺的优缺点和操作技巧.     

国内外V法铸造技术的发展现状与问题

总结了国外V法铸造发展的3个特征:①设备大型化和小型化并进;②在铸钢和球铁生产上优势凸显;③铝合金和镁合金铸件具有潜在优势;归纳出国内V法铸造技术上的5个突破:①EVA塑料薄膜实现系列化和标准化;②自主创新、拥有自主知识产权的大型V法造型线;③采用CAD/CAM技术、提升了V法铸件质量;④V法铸造真空系统的控制与节能技术;⑤在铸钢、球铁和铝合金铸件上应用获得突破,以及存在机械化程度不高、铸造环境差、V法铸造低碳不锈钢有增碳现象等问题.     

用V法造型工艺铸造机床大板

介绍了用V法造型工艺生产T型槽机床大件和配重铁的生产经验.实践证明,V法铸造生产铸铁、铸钢大件能够实现提高产品质量、降低成本、减轻劳动强度、提高经济效益的目的.     

中小型铸件V法铸造生产线设计

根据中小型铸件V法铸造生产线的特点,阐述了V法造型线的工艺流程和主要技术参数,分析了砂处理系统需要解决的问题,并介绍了V法铸造生产线的主要设备.V法铸造生产线采用半自动化控制,可缩短生产周期,提高生产效率.     

V法铸造工艺装备与技术特性

介绍了V法铸造工艺的主要设备与其技术特性.分别介绍了各设备在造型、砂处理各工序环节的基本应用状态和相关的技术特性.通过探讨V法铸造生产的工艺及技术特性,以拓展V法铸造工艺装备与生产的发展前景.     

文摘荟萃

V法的现状和展望原载《金属》1987年第2期42～45页作者[日]土田正信等V法出现已经十五年了,现已普及到世界各国。V法技术也有了很大的进步。 1.V法造型的特征 V法使用塑料薄膜,铸件轮廓清晰、表面光洁、起模斜度小,模板磨损小、使用的寿命长。V法使用干砂,故填充性能好,砂处理简单,设备费用低,作业环境好。V法利用真空技术,造型迅速、落砂方便。 2.V法铸造产品的特点和V法现状浴盆是V法铸造生产的典型产品之一。其     

V法造型线砂处理系统的设计与应用

随着人们对V法造型认识的增加和V法技术掌握程度的提高,V法造型线在生产中的使用越来越多,与之配套使用的V法砂处理系统的的磁选问题,成为V法生产中的瓶颈。本文介绍了一种V法造型线砂处理系统新的设计思路、组成和工作特点。经生产实践证明,该V法砂处理系统有效解决了V法造型线砂处理系统磁选的难题,满足了造型线的生产需求,提高了生产率。     

V法铸造缺陷烂砂的原因分析与控制措施

介绍了特种铸造——V法铸造过程中烂砂或坍塌缺陷产生的原因.通过对V法铸造充型过程中干砂-液态金属界面、干砂-气隙界面平衡条件的分析,得出保持铸型稳定性的条件.提出了通过工艺设计、真空度控制、浇冒口设计等控制措施防止V法铸造生产过程中烂砂、坍塌等缺陷的发生.     

V法铸造工艺创新实践

针对V法铸造常见的问题提出了两种创新性实践:1)采用垂直分型工艺解决生产中小型铸件的难题.2)通过对潮模砂与V法造型相结合复合工艺的探索解决V法铸造对真空系统的依赖和粉尘问题,并提出工艺复合建议.     

V法铸造铝合金的发展现状

综述了国内外V法铸造铝合金工艺的研究进展,列举了国内外典型V法铸造铝合金企业及其产品应用范围,通过对树脂砂、粘土砂、V法铸造工艺生产的铝合金铸件进行粗糙度、硬度、针孔度检测对比,为生产高品质的V法铸造铝合金件作为参考。     

Comparison of geometries and electronic structures of polyacetylene,polyborole, polycyclopentadiene,polypyrrole, polyfuran,polysilole, polyphosphole,polythiophene, polyselenophene and polytellurophene

Geometries of monomers through hexamers of cylopentadiene, pyrrole, furan, silole, phosphole, thiophene, selenophene and tellurophene, and monomers through nonamers of borole were optimized employing density functional theory with a slightly modified B3P86 hybrid functional. Bandgaps and bandwidths were obtained by extrapolating the appropriate energy levels of trimers through hexamers (hexamers through nonamers for borole) to infinity. Bandgaps increase with increasing π-donor strengths of the heteroatom. In general, second period heteroatoms lead to larger bandgaps than their higher period analogs. Polyborole is predicted to have a very small or no energy gap between the occupied and the unoccupied π-levels. Due to its electron deficient nature polyborole differs significantly from the other polymers. It has a quinoid structure and a large electron affinity. The bandgaps of heterocycles with weak donors (CH₂, SiH₂ and PH) are close to that of polyacetylene. For polyphosphole this is due to the pyramidal geometry at the phosphorous which prevents interaction of the phosphorus lone pair with the π-system. The bandgap of polypyrrole is the largest of all polymers studied. This can be attributed to the large π-donor strength of nitrogen. Polythiophene has the third largest bandgap. The valence bandwidths differ considerably for the various polymers since the avoided crossing between the flat HOMO — 1 band and the wide HOMO band occurs at different positions. The widths of the wide HOMO bands are similar for all systems studied. All of the polymers studied have strongly delecalized π-systems.     

Supplemental Literature Review of Binary Phase Diagrams: Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr

Recent literature on Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified.     

Supplemental Literature Review of Binary Phase Diagrams: Bi-Ce, Bi-Er, C-Ce, C-La, C-Pr, Cd-I, Cr-Cu, Cu-Er, Er-Sb, F-Sm, F-Yb, and Fe-Gd

Recent literature on Bi-Ce, Bi-Er, C-Ce, C-La, C-Pr, Cd-I, Cr-Cu, Cu-Er, Er-Sb, F-Sm, F-Yb, and Fe-Gd phase diagrams is reviewed in this article in order to update the 1990 compilation Binary Alloy Phase Diagrams, 2nd edition, by T.B. Massalski, et al. For some systems reaction tables and crystal structure data have been included, as well. Diagrams have been checked for consistency with rules for phase diagram construction and modified when necessary. In addition, diagrams needing more work have been identified.