钨合金废料的资源再生利用技术

钨是一种稀有金属,钨合金具有高强度、高硬度、较好的耐高温性、耐磨性和良好的电性能,被广泛地应用于航空航天工业、兵器工业、核工业、信息产业、汽车工业和钢铁工业等行业。目前,钨资源短缺,钨合金价格高、用量大,因此各国都把废弃的钨合金作为宝贵的第二钨资源加以再生利用。作者综述了钨合金的再生利用现状,总结了硬质合金、高比重合金、钨铜合金和钨材的再生利用技术,并从生态环境材料的立场出发,对每种再生利用技术作了简要的评价。     

钨基高比重合金技术的发展

钨基高比重合金是钨的最重要的两大市场之一，是现代工业经济不可缺少的组成部份。近年来，由于钨基高比重合金技术的发展，已造就一系列高性能材料，其使用周期成本及环保方面的优势均明显胜过与之竞争的其它高比重材料。     

细晶钨合金密度均匀性研究

采用喷雾干燥法制备超细钨合金粉末,利用低温烧结技术烧结出致密度达到99%以上的细晶钨合金坯料,分别对同炉烧结的不同坯料和同一件坯料的纵向和横向分别切割测试密度均匀性。结果显示,同炉坯料密度均匀性与常规钨合金区别不大,但同一件坯料纵向和横向密度均匀性分别达到99.924%和99.936%,比常规钨合金密度均匀性提高了0.882%,并从微观组织形貌上对密度均匀性与常规钨合金的区别做了初步分析。     

再生高比重钨合金塑性的研究

对再生高比重钨合金塑性的提高作了较为深入地研究。研究表明:向再生合金原料粉末中加入适量的Ni、Fe元素进行成分调节可显著提高再生合金的塑性;对再生合金进行真空热处理可明显提高再生合金塑性,与热处理前相比,再生合金延伸率提高了约43.42%,截面收缩率提高了约33.88%。     

难熔钨合金与硬质合金的研究新动向

难熔钨合金和硬质合金在工业中应用很广泛,本文主要介绍近年来在超细/纳米钨合金和硬质合金粉末和合金制备技术方面的研究新进展,重点阐述了注射成形、喷雾转换、溶胶-喷雾干燥-热还原以及合金的晶粒控制等技术,并指出了今后钨合金和硬质合金的研究发展方向。     

钨的冶金及其加工技术

简要综述了钨的冶金和加工技术。除了用于制备高纯金属以及单晶等场合之外,钨及其合金的制备仍以粉末冶金方法为主,但近些年来在纳米钨粉的制备、掺杂钨合金的研究、钨合金的注射成形和复合材料的制备方面有很快地发展。     

钨铼合金研究进展

随着航空航天技术、核工业、电子工业的日益发展,对超高温材料提出了更为苛刻的要求,急需研制高温高强度结构件材料。钨铼合金具有高再结晶温度、低韧脆转变温度、优异的高温强度以及高温抗蠕变性能,得到了国内外学者的广泛研究。本文综述了钨铼合金的分类及制备方法,并对固溶强化钨铼合金、碳化物增强钨铼合金、氧化物增强钨铼合金的再结晶温度、高温强度、高温抗蠕变性能等进行了比较,认为碳化物（Hf C）增强钨铼合金具有更加优异的性能。因此,碳化物第二相粒子增强钨铼合金是钨铼合金的发展方向并且有必要对钨铼合金的先进制备技术、成分优化、组织调控、变形行为和机理等问题开展进一步研究。     

高比重W—Ni—Fe合金的变形强化

在三个钨含量的Ｗ－Ｎｉ－Ｆｅ合金变形强化过程中，研究了变形量和力学性能与显微组织之间的关系。试验结果表明：随着钨合金变形量的增加，变形合金的强度和硬度亦增加，当变形量超过１５％后，高钨含量合金的变形强化作用逐渐减小。在变形合金的显微组织中，钨颗粒沿棒料轴向明显拉长，同时解理断裂成为断口的主要形式，并显现出钨合金断面上的滑移带。本文还讨论了变形合金在真空下，最佳调质退火温度和两相钨合金的形变特点、变     

钨合金的开发和应用现状

简单叙述了钨合金的特点,介绍了钨及钨合金在耐震钨丝、复合稀土钨电极和军事上的穿甲弹、钨子弹、药型罩的开发和应用。     

高比重钨合金的金属注射成形技术

概述了金属注射成形技术的基本工艺过程及其特点，从几种金属注射成形典型工艺分析入手介绍了金属注射成形技术的发展状况，最后介绍了该技术在高比重钨合金中的应用。     

Remelting of scrap containing tungsten and nickel in the electric arc furnace

Remelting of the metallic scrap containing tungsten and nickel and thermodynamic properties of slag containing tungsten oxide are discussed. Tungsten and nickel in the metallic scrap have to be separated before the scrap may be used for melting of some steels (for example, high speed steel). To separate tungsten and nickel, such scrap (waste drills) was remelted in the 25 t electric arc furnace under oxidizing conditions. Tungsten was oxidised and transferred to the slag phase, while nickel remained in the metal. Further, the slag containing tungsten oxide was used in the melting of high speed steel. Metal containing nickel was utilized in the constructional steel production. Technology of the scrap remelting was developed on the basis of thermodynamic analysis of slag containing tungsten oxide and tungsten slag-metal partition. It was found that the coefficient of tungsten distribution between iron and basic CaO-SiO₂-Fe_tO-WO₃ slag increases with increasing slag basicity. In the industrial oxidising heats a slag of high basicity was used, it secured 94% tungsten extraction from scrap to the slag.     

Preparation of Hard Alloy WC and WC – Co Mixtures with Reduction and Carbidizing Treatment of Oxidized Tungsten Containing Scrap

A method of single-stage reduction and carbidizing treatment of oxidized tungsten containing scrap (hard alloys of the VK type and tungsten wire) is proposed. Procedures are suggested for preparing very fine tungsten carbide of stoichiometric composition without adding carbon black by reduction and carbidizing treatment of oxidized tungsten wire scrap and also with introduction of solid carbon (carbon black) during reduction and carbidizing treatment of oxidized hard alloy scrap.     

细晶钨合金内部组织均匀性研究

喷雾干燥法制备超细粉末,使用低温烧结技术制备钨合金制品,分别对超细钨合金和常规钨合金进行力学性能测试,并采用超声波探伤技术检测超细钨合金和常规钨合金的内部组织,探伤结果显示超细晶钨合金内部没有发现缺陷,而常规钨合金内部有两处鸟巢状缺陷,分别对缺陷部位和没有缺陷部位进行金相分析,金相显示缺陷部位是液相缺失导致的钨颗粒聚集,聚集的钨颗粒没有液相填充出现很多孔洞。     

Sintering of Tungsten and Tungsten Heavy Alloys of W–Ni–Fe and W–Ni–Cu: A Review

Tungsten is a refractory metal possessing good mechanical properties of high strength, high yield point, and high resistance to creep. Therefore, tungsten and its alloys are used in many high temperature applications. Due to the high melting point, they are generally processed through powder metallurgy method. The powders are compacted using die pressing or isostatic pressing. The compacts are sintered in a sintering furnace to achieve high density, thereby, making the metal suitable for further processing. This article reviews the recent research findings of consolidating tungsten and its alloys (W–Ni–Fe and W–Ni–Cu), from preparation of powder alloys to sintering of the compact. The advances in sintering are based on the objective of achieving good densification of the metal at lower temperature and at faster rate. The use of microwave sintering and spark plasma sintering techniques resulted in significant reduction in sintering time and producing products of good mechanical properties.     

钨铼合金制备方法和高温力学性能的研究进展

高性能W-Re-ThO2,W-Re-HfC系钨铼合金的制备和性能研究会促进其在电子、核能、航天和测温技术等领域的应用。详细归纳了W-Re-ThO2和W-Re-HfC两种钨铼合金采用的工艺路线和工艺参数,总结了两种合金在不同成分和加工状态下时的高温力学性能,最后探讨了铼效应对钨铼合金高温性能影响的规律。钨合金的研究目前在向细化、纯化和强韧化方向发展,粉末冶金法是制备钨铼合金合适的工艺路线,因此开展第二相粒子强化的钨铼合金组织和性能的研究是非常重要的研究内容和方向。     

Technologies of secondary refractory rare metals (Review)

A short review of works by A.V. Elyutin et al. in the field of rare metals is presented. Technologies of the recovery of zirconium, hafnium, tungsten, tantalum, and niobium from various types of secondary raw materials, notably, scrap metal, scrap of refractory materials, wastes and scrap of hard alloys, and obsolete scrap of capacitors, are considered. Possibilities of increasing the purity of these metals by electrolytic refining and electron-beam melting are shown.     

厦门钨业钨资源综合回收利用

结合中国钨资源以及近5年中国钨消费情况,介绍了厦门钨业对废钨、低品位白钨矿、高杂钨矿、黑白钨混合矿等钨资源综合回收利用的实际情况和冶炼技术。     

Advanced technology in tungsten and moly PM

Worldwide consumption of tungsten and molybdenum was 44 000 tonne and 97 000 tonne, respectively, in 1988. But only a small percentage of this volume is processed to pure or alloyed semifinished or finished products. Some 6% of all molybdenum consumed (5000 to 5500 tonne) is in the form of molybdenum and molybdenum alloys. For tungsten this percentage is higher, 10% of tungsten consumed was pure tungsten or tungsten alloy products. The same amount was produced as heavy metal every year, totalling 8000–9000 tonnes of tungsten content in tungsten and tungsten based alloys including heavy metal, says Ralf Eck of Metallwerk Plansee.     

Nickel-base superalloys; physical metallurgy of recycling

Because of stringent performance specifications, alloys included in the category of nickel-base superalloys are some of the most metallurgically complex and expensive in the field of metallurgy. The fact that these complex alloys can be manufactured commercially to make reliable components reflects the skill which alloy producers apply to control composition to meet rigid specification of trace elements as well as alloy constituents. Nevertheless, a substantial amount of scrap is used in the manufacture of these alloys, and highly specialized operations have been developed to process this scrap. This paper provides an overview of the current use of scrap in the industry and procedures for handling, melting, and refining scrap. The effects of residual elements commonly encountered in superalloy scrap on structure and properties are reviewed. Finally, a brief assessment of trends in generation and use of scrap is presented.