镁合金无熔剂熔炼防燃净化技术研究进展

介绍了镁合金熔体中常见的气体和夹杂物,概述了目前国内外先进的镁合金无熔剂熔炼防燃保护气体和精炼净化方法,着重介绍了NovecTM612熔体保护气、旋转喷吹气体净化法以及泡沫陶瓷过滤,分析了我国镁工业的现状,并指出了将来我国镁合金研究者和工作者的研究重点.     

用于熔炼变形稀土镁合金的专用熔剂制备及性能试验

对自制的两种用于熔炼变形稀土镁合金的专用熔剂,采用差热分析和扫描电子观察及能谱分析方法研究了其对熔炼的镁合金显微组织的影响;并对比两种覆盖剂在熔炼的不同阶段所起的作用。其中,1#覆盖剂在低温熔炼阶段具有较好的保护熔体的效果,但高温下其粘度大幅下降而降低保护效果;2#熔剂因含较多的Ca F2和Mg F2,可加大熔剂密度和稳定性,不但有良好的保护熔体的作用,同时具有提高熔剂的造渣能力而起到更好的精炼效果。     

吹入气体和熔剂混合物精炼铝合金

为了精炼铝合金采用各种方法:用惰性气体吹洗熔体、用熔剂进行处理及其他方法。此时,用一种方法除气效果不错,但从金属中清除氧化物颗粒效果较差(吹气法)或者与此相反(熔剂处理法)。吹入惰性气体时,熔体除气速度慢,只好增加吹气时间和增多气体耗量。通常采用的气体(氮、氩)含有一定量的氧和水蒸气,它们活泼地氧化铝熔体,在气泡表面     

熔化条件和除气工艺对镁熔体含氢量的影响

利用自行开发的镁合金定量测氢仪研究了熔化条件和除气工艺对镁熔体含氢量的影响。研究结果表明,镁熔体中的含氢量随温度的升高而增大;气体保护下熔炼比熔剂保护的效果好,含氢量较低;随保温时间的延长,气体保护下的镁熔体含氢量几乎没变化,而熔剂保护下的含氢量成小幅上升趋势;采用Ar气除气工艺的效果比C2Cl6除气更有效,镁熔体含氢量更低。     

镁合金精炼用新熔剂的研究

一、前言镁及其合金是一种极易氧化的金属,特别是在熔融状态下更易氧化燃烧,为了减少烧损,安全生产和保证金属内部纯洁度,在整个熔铸过程中需要用气体或熔剂加以保护。目前变形镁合金铸锭的生产是用粉状的二号熔剂作熔体表面的复盖保护。二号熔剂加10％(或15％)氟化钙制成粉状或块状作为镁合金熔体的精炼熔剂。铸造时用二氧化硫气体保护。二号熔剂主要成分为氯盐。氯盐熔剂的采用除对熔体起保护作用防止氧化燃烧外,还兼有精炼除渣、除气的作用。然     

复合精炼对Al-Si合金净化效果的试验研究

研究了复合精炼对铝硅合金熔体的净化效果，并介绍了铝硅合金熔体中主要氧化夹杂物与气体的存在形态及其相互作用。试验结果表明：在铝熔体较少的情况下，复合精炼法是精炼铝硅合金，降低含气量最有效的办法．其净化效果优于试验中常用的吹气法和熔剂法。     

镁熔体净化技术的研究进展

镁作为新兴轻质材料在汽车、3C和航空航天领域的应用逐渐普及,伴随行业节能减排的要求提升以及材料行业的迭代更新,镁及其合金所涉及的产业领域将会进一步扩大。而镁及其合金在铸造与变形加工前,镁熔体纯净度会对其性能产生巨大影响,如熔体纯净度低会显著降低合金的抗拉强度、伸长率等力学性能,导致合金出现炸裂、破损现象。为此,镁熔体的高效除气除杂净化技术成为研究热点。镁熔体净化作为镁熔炼过程中的重要环节,一直是科研工作者不断改进优化的研究课题。本文在简要介绍镁熔体中夹杂物来源的基础上,归纳了适用于镁熔体的熔剂净化、无熔剂净化、复合净化法及其净化效果,且对真空蒸馏法净化镁熔体的相关研究进行了探讨,系统综述了镁熔体净化技术研究进展,展望了该技术的未来研究方向。     

国外关于镁精炼工艺及镁应用的研究

在镁熔炼技术方面,70年代的一大发展是以六氯化硫保护气氛精炼镁。过去通常采用的熔剂保护外加热敞口坩埚精炼镁,热效只有10～25％,污染环境,腐蚀设备。国际镁研究中心巴蒂尔哥伦布研究室研究了以空气加0.04～1.5％六氟化硫为保护气氛精炼镁或AZ91B合金的方法,与原采用的熔剂精炼法比较,熔炼损失可减少一半,热效提高一倍,成本低而无污染。采用SF6-空气混合气作为镁精炼的保护剂,适宜的熔炼温度范围为705～760℃,同时     

提高10吨精炼炉熔炼外购镁精炼回收率的实践

以镁法海绵钦生产工艺的生产实际情况为依据,介绍了自产镁不足的精况下,采用外购镁锭熔炼以满足海绵钛的生产需要.通过采取加入高密度电解质和改变原熔剂成分等措施,显著地提高了精炼炉熔炼外购镁精炼回收率,实现了节能降耗地为还蒸工序提供优质、充足的熔体精镁,降低了镁工序的生产成本.     

镁合金无熔剂冶炼

综述了目前国内外镁合金冶炼中熔体保护和精炼这两项重要工艺内容的基本原理及方法.分析了熔剂、合金元素、气体保护等熔体保护的方法和熔剂精炼、喷吹气体精炼、过滤精炼等其它精炼方法在镁合金冶炼中的作用及特点.总结并提出了镁合金无熔剂精炼工艺的基本方法,指出镬合金无熔剂冶炼中还存在的问题以及今后研究、发辰的方向.     

镁合金净化技术研究现状及展望

镁的性质很活泼,在熔炼过程中会产生大量夹杂和气体,大大降低了其合金性能。介绍了合金中夹杂和气体的种类及来源,综述了目前国内外镁合金净化技术的研究进展,如吹气法、熔剂净化法、过滤法、稀土净化法、电磁净化法等,并讨论了其机理,展望了净化技术的未来发展。     

镁合金净化工艺研究进展

夹杂物会使镁合金性能下降,纯净化是镁合金扩大运用范围的关键之一.本文综述了镁合金净化工艺研究进展,包括熔剂净化和非熔剂净化中的吹气净化、过滤净化、沉降净化、稀土净化、复合净化等,并对镁合金净化技术的未来进行了展望.     

亚共晶Al—Si合金熔体处理的研究进展

评述了近年来在亚共晶Ａｌ－Ｓｉ合金的净化、变质和晶粒细化等熔体处理领域所取得的进展，指出将喷射熔剂法用于整个熔体处理过程是今后的发展趋势。     

Purifying effect of new flux on magnesium alloy

1　INTRODUCTIONAsoneofthelighteststructurematerials ,mag nesiumalloysofferlightmass(ρ<2 g·cm- 3) ,specif icstrength (higherthanthatofthealuminumalloysandsteels) ,specificstiffness ,excellentmachinabili ty ,superiordampingandmagneticshieldingcapaci ties,whichleadstoagrowinginterestinmagnesiumanditsalloys .Inrecentyears ,magnesiumalloyshavebeenwidelyusedinaviation ,spaceflight,automobileandelectronicsindustries[1] .Since 1990 stheirappli cationhassteadilyextendedanditispredictedthatitwill…     

Mechanism to remove oxide inclusions from molten aluminum by solid fluxes refining method

A novel flux charging method and a crucible quenching method were employed to study the mechanism of solid fluxes refining method regarding the removal of oxide inclusions (Al2O3) from molten aluminum.Electrochemical polishing method was adopted to prepare surfaces of the samples.Through experiments,the morphology of the residual solidified flux in the solidified samples as well as the wetting action of the molten flux during refining were observed for the first time.Three wetting regimes denoted by absorbing regime,engulfing regime and penetration regime correlating with the removal of oxide films (the most typical and common oxide inclusions in molten aluminum) were proposed in terms of different types and distributions of oxide films and different size ratios of the molten flux to oxide films.Particularly,from a thermodynamic point of view,for the first time,the penetration regime provided concrete evidence that the practical oxide inclusions can be wet by molten flux under ambient fluid of molten aluminum.A spreading model was proposed,according to which ingredients and size parameters of practical solid fluxes can be optimized.     

Mechanism of boron removal from Si–Al melt by Ar–H2 gas mixtures

A new method about purification of metallurgical grade silicon (MG-Si) by a combination of Si–Al solvent refining and gas blowing treatment was proposed. The morphologies and transformation of impurity phases, especially for boron and iron in Si–Al melt were investigated during Ar–H₂ gas blowing treatment. The mechanism of boron removal was discussed. The results indicate that gas blowing can refine grain size and increase nucleation of the primary Si. Boron can be effectively removed from MG-Si using the Ar–H₂ gas blowing technique during the Si–Al solvent refining. Compared with the sample without gas blowing, the removal efficiency of boron increases from 45.83% to 74.73% after 2.5 h gas blowing. The main impurity phases containing boron are in the form of TiB₂, AlB₂ and VB compounds and iron-containing one is in the form of β-Al₅FeSi intermetallic compound. Part of boron combines [H] to transform into gas B_xH_y (BH, BH₂) and diffuses towards the surface of the melt and is volatilized by Ar–H₂ gas blowing treatment under electromagnetic stirring.     

高效排杂溶剂过渡净化工业纯铝

探讨了熔剂过渡净化工业纯铝的效果及其净化机理。结果表明：合适的熔剂组成及处理工艺是保证其具有高效排杂作用的关键：采用特定的溶剂（CJ－5）和过渡工艺,在适当的加入量（3％）和熔炼温度（720℃）条件下,对不同纯铝的除杂率和针孔率降低幅度分别可达70％－82％和60％－88％,显著提高了材料的强度和塑性,尤其是塑性可提高约70％;其高效排杂作用的关键在于该方法具有将铝的溶化－溶剂过滤－溶剂吸杂溶杂三个过程实现于溶炼全过程中的独特性,符合以排杂为主的净化原则,充分发挥了熔剂排杂净化效率。     

Grain refining action of Ti existing in electrolytic low-titanium aluminum with Al-4B addition for superheated Al melt

The effects of superheating temperature on the grain refining efficiency of Ti existing in electrolytic low-titanium aluminum (ELTA) without and with the Al-4B addition and the Al-5Ti-1B master alloy in pure Al were comparatively investigated. The results show that the Ti existing in ELTA without Al-4B addition exhibits a certain grain refining efficiency when the melt superheating temperature is lower, but the efficiency decreases rapidly when the superheating temperature is higher. The grain refining efficiency of the Al-5Ti-1B master alloy is better than that of the Ti existing in ELTA without Al-4B addition at any superheating temperature, but it also decreases obviously with the increase of the superheating temperature. One important reason is that the TiB2 particles coming from the Al-5Ti-1B master alloy can settle down at the bottom of the Al melt easily when the superheating temperature is increased, thus decrease the number of the potent heterogeneous nuclei retained in the Al melt. If the Al-4B master alloy is added to the ELTA melt, the grain refining efficiency of the Ti existing in ELTA can be improved significantly, and does not decrease with the increase of the superheating temperature. This perhaps provides us a possible method to suppress the effect of the superheated melt on the microstructures of aluminum..     

镁合金熔剂净化研究现状与展望

镁合金化学性质极其活泼，极易与氧、氮、水汽等发生化学作用，产生大量的非金属夹杂物和金属夹杂物，严重恶化了镁合金的铸造性能、力学性能及耐腐蚀性能。阐述了镁合金中的夹杂物来源及其危害，综述了镁合金净化熔剂的研究现状，并对熔剂的研究发展方向进行了展望。     

镁及镁合金的晶粒细化

叙述了镁及镁合金晶粒细化的几种方法，如熔剂处理法、熔体过热法、熔体搅拌法、合金化细化晶粒、固态变形处理、半固态成形及快速凝固工艺等。细化镁合金晶粒尺寸能显著提高其力学性能，这对推广镁合金的应用具有重要意义。