浅谈提高重熔用铝锭外观质量的生产措施

中国铝业青海分公司主要产品为20kg重熔用铝锭，由60t倾翻炉、电磁搅拌器、20kg连续铸造机等主要设备，组成整体的铸锭工艺生产线。随着国民经济的发展，企业对重熔用铝锭内部质量和外部质量都有了更高的要求。产品质量除国家标准和企业标准外，公司还制定了内部控制产品外观质量的标准，以此促进经济效益。为了进一步提高重熔用铝锭产品的外观质量，减少不合格品返工带来的能源浪费和污染物排放，公司采取了相应的措施。     

重熔用铝锭质量和标准浅析

回顾了我国重熔用铝锭标准的演变历史,提出了进一步提高铝锭质量和完善铝锭标准的建议。认为应该根据我国的原料特点,标准中应规定控制标准,并使我国的标准向国际标准和国外先进标准看齐,还应逐步向统一锭型过渡,解决铝锭的包装问题。     

从改变产品结构出发进行铝厂技术改造

我国所有铝冶炼企业,基本上是生产一个品种的产品——铝锭。这种单一化的产品结构,是对能源的巨大浪费,是对人力、物力的巨大浪费,一句话,在经济上是很不合算的。绝大多数的铝锭用户不是直接用固体铝加工自己所需要的产品,几乎无一例外的要对铝锭进行重熔,掺进去其他金属元素变为合金,然后再变成各种坯料,用来加工各种产品。合金企业,把铝锭重熔后先变成母合金,然后再生产出所需要的合金;电缆厂把铝锭重熔后铸成铝杆,再拉制电缆和电线;铝材企业要把铝锭重熔后变成板锭,再来     

电解铝液生产铝材坯料的工艺技术

介绍了电解铝厂电解铝液的特性，分析了用电解铝液直接生产铝材坯料的工艺技术以及与铝锭重熔法相比的经济效益。     

99．85铝锭裂纹的产生及防止

1 99.85铝锭的铸造生产工艺 1.1 99.85铝锭的内部成分要求 根据国家标准GB1196-2002对重熔用铝锭化学成分的规定,99.85铝锭的主要化学成分及杂质含量应符合表1的要求.     

电解铝液直接铸造板坯的技术发展

熔铸是热轧前工序，坯料质量的高低直接影响最终产品质量，因此，开展热轧坯料铸锭技术的研究与开发已成为我国铝加工企业重点关注的技术问题。目前国内铝加工企业大多采用从电解铝厂购置重熔铝锭，在自建熔铸生产线上通过铝锭重熔、熔体精炼、铸锭等过程获得热轧坯料，这种工艺造成坯料的加工成本居高不下。直接影响企业的经济效益。目前国内只有少数厂家采取用电解铝液直接铸轧工艺生产铝线杆和低档次铸轧卷。而美、欧发达国家有60％。70％的电解铝液被直接浇铸成加工用铝合金锭坯。     

积极“采标”增强企业活力

在“八五”期间,抚顺铝厂极其重视采用国际标准和国外先进标准工作。 由中国有色总公司标准计量所确认和省技术监督进行验收的采用国际标准产品项目有重熔用铝锭、重熔用镁锭、工业硅、海绵钛、高五号铝锭、铝合金建筑型材、铸造铝合金、6063铝合金、电工用铝锭、镁合金牺牲阳极、铸轧铝板卷等11项,还计划在1995年第四季度对产品ZLA356铸造铝合金、     

简议中国铝资源的进口

中国铝矿资源短缺,其品质也不尽人意,同时也是能源并不富裕的国家,一直是一个铝资源净进口国,这种态势将继续延续下去。进口的铝资源有:铝土矿、氧化铝、重熔用铝锭、铝合金锭、废铝(含拆解装备获得的废铝)、铝材、铝制品。进口重熔用铝锭是上策,进口铝土矿是下策,而到国外建氧化铝厂、电解铝厂然后运回铝锭是最佳途径。     

用电解铝液轧制圆铝杆的净化工艺

圆铝杆是生产铝线和挤压圆管的坯料,大多数铝加工厂使用重熔用铝锭生产圆铝杆,而直接使用电解铝的较少。因为使用电解铝液直接生产圆铝杆与使用重熔用铝锭相比更节能,但由于电解铝液中杂质较多,产品会存在质量上的缺陷。本文从缺陷产生的原因和相关措施对铝液的净化工艺进行了浅析。     

2013年中国进口氧化铝3830kt,净进口重熔用铝锭256kt

<正>据海关统计:2013年中国进口氧化铝3 830 kt,同比下降23.7%,由于国内氧化铝价格不断走低,国内外价差不利于进口,故全年进口量有所减少;2013年中国重熔用铝锭进口372 kt,同比下降28.3%,出口重熔用铝锭116 kt,同比下降6.7%,因此净进口量256 kt。     

Morphology and corrosion characteristics of laser surface remelted Al‐Si alloy at cryogenic conditions

The properties and consequently functionality of equipment made of aluminium alloys are influenced by microstructural characteristics such as phase composition and grain size distribution in their surface layer. Nowadays, many surface engineering techniques have been applied to improve the surface properties of aluminium alloys, one of them being laser surface treatment. The effect of laser surface remelting at cryogenic conditions on the local chemical compositions, microstructure and corrosion characteristics of AlSi13Mg1CuNi aluminium alloy have been presented. The beneficial effect of laser treatment on the corrosion behaviour of the cast aluminium alloy in 0.01 M sulphuric acid solution was observed.     

Corrosion and electrochemical behavior of aluminium treated with high-temperature pulsed plasma in CsCl–NaCl–NaNO3 melt

Dense protective layers of aluminium corrosion products, whose composition depends on the oxidation temperature, are formed on the surface of aluminium treated with high-temperature pulsed plasma (HTPP) without visible remelting and then held in a chloride–nitrate melt in conditions of anodic polarization. Modification of aluminium treated with HTPP changes the properties of 20 μm layer under its surface and the oxide layer formed by such treatment has different morphology: it consists of smaller crystals and so has the other protective properties as compared with aluminium untreated by plasma.     

Experimental characterisation of a semi-solid A356 alloy during solidification and remelting

Abstract

Within the general framework of hot tearing research in casting processes the tensile behaviour of the semi-solid aluminium alloy A356 under remelting and solidification conditions is studied. In order to measure true-stress versus true-strain curves of the semi-solid metal, a new experimental technique has been developed to perform hot tensile tests in the mushy regime between the coherency and the solidus temperatures. The local true-strain in the semi-solid region of the tensile specimen is measured optically with a laser speckle extensometer (LSE). During the solidification tests measurement is done by using a transparent aero-gel mould. The resulting stress–strain curves and the corresponding microstructure are compared for the remelting and solidification condition.     

自耗电极自动进给系统下的电渣熔铸工艺参数优化

采用正交试验法,优化出自耗电极自动进给系统下的电渣熔铸工艺参数.按该工艺参数,所获铸锭内外质量好,重熔效率高.文中认为:工作电流和渣量是主要的控制因素,冷却水量是次要因素.     

Processing of high carbon Fe3Al based intermetallic alloy

A melting procedure for air induction melting (AIM) of an Fe₃Al based intermetallic alloy Fe-15.38 wt%Al-1.1 wt%C is described. Use of an appropriate slag cover during AIM results in elimination of hydrogen gas porosity in cast AIM ingots. Criteria for slag selection and slag to metal ratio are discussed. Refining by slag-metal reactions results in significant reduction in impurity levels (S, O, N) during AIM. Consequently, low cost raw materials such as mild steel scrap and commercial aluminium were used for melting the alloy. The AIM ingot exhibited excellent tensile properties. The ductility and hot workability of the ingot may be further improved by subsequent processing through electroslag remelting. It is also argued that the presence of carbon may be necessary to get AIM castings with desirable mechanical properties.     

高频感应重熔智能运控系统的研究与应用

为了解决传统感应加热设备因缺少智能运控系统而导致的重熔涂层质量不稳定的难题,对高频感应重熔智能运控系统的结构与组成、运行模式等进行设计,实现了对高频感应重熔集成装置的智能跟踪可控功能。通过该系统制备了NF201镍基自熔性合金粉末重熔涂层,并与等离子喷焊技术制备的涂层进行微观组织与硬度对比分析。结果表明:相对于等离子喷焊涂层,采用高频感应重熔智能运控系统制备的重熔涂层具有更优异的组织结构和力学性能,其微观组织更为致密细腻,孔隙率及缺陷尺寸较小,硬度较高,硬度极差较小,从而验证了此智能运控系统能够有效提升感应重熔涂层的质量。     

Method for determining reaction rate of mild steel containers during melting of magnesium-aluminium alloys and effect of aluminium content on directionally solidified microstructures

A magnesium alloy of eutectic composition (33 wt-%Al) was directionally solidified in mild steel tubes at two growth rates, 32 and 580 μm s^?1 in a temperature gradient between 10 and 20 K mm^?1. After directional solidification, the composition of each specimen varied dramatically, from 32%Al in the region that had remained solid to 18%Al (32 fim s^?1 specimen) and 13%Al (580 (μm s^?1 specimen) at the plane that had been quenched from the eutectic temperature. As the aluminium content decreased, the microstructure contained an increasing volume fraction of primary magnesium dendrites and the eutectic morphology gradually changed from lamellar to partially divorced. The reduction in aluminium content was caused by the growth of an Al-Fe phase ahead of the Mg-Al growth front. Most of the growth of the Al-Fe phase occurred during the remelting period before directional solidification. The thickness of the Al-Fe phase increased with increased temperature and time of contact with the molten Mg-Al alloy. IJCMR/455     

激光重熔技术在选区激光熔化中的研究进展

激光重熔使得材料表面的固化层再次快速熔化、凝固，从而提高了材料的致密度和表面质量。作为一种表面改性技术，激光重熔已经在传统制造工艺中得到了广泛的应用。近期研究表明，激光重熔技术也可以应用到选区激光熔化（SLM）中，实现消除缺陷并优化组织结构。激光重熔技术还可以提高零件的硬度和延展性等力学性能。本文主要总结了激光重熔对于常见SLM成形金属材料的质量提升作用，激光重熔工艺手段以及重熔参数（重熔激光功率、重熔扫描速度、重熔扫描间距和重熔次数）对于缺陷消除、组织结构优化的作用规律。     

熔体混合处理对A356铝合金组织的影响

采用熔体混合技术处理A356铝合金,并通过再次重熔加热研究熔体混合处理细化效果的稳定性。利用光学显微镜观察合金组织,用Image Pro金相分析软件测定了初生α-Al相的平均直径。结果表明,熔体混合技术能较好地细化A356铝合金中的初生α-Al相,且A356铝合金的熔体混合处理在650℃下具有较好的一次重熔稳定性。     

用模铸八角锭作为自耗电极生产H13钢电渣重熔锭

通过调整电渣重熔时的冶炼工艺参数,直接以截面差异较大的5.0 t模铸八角锭作为电渣重熔用自耗电极,生产出了质量优良的H13钢电渣重熔锭。该工艺可降低生产成本、缩短生产周期。