Figure 1. The photo at left shows alkaline phenolic resin molds four hours after pouring. At right are Bangni resin molds 10 minutes after pouring.
图1是邦尼树脂砂型和碱性 酚醛树脂砂型浇注后情况 的对比。
In the last 10 years, the German metalcasting industry has
carried out comprehensive and intensive research on silicate binders, in cooperation with various companies and institutes, which include: • Global binder manufacturers such as ASK and HZ, which engaged in the research and development of silicate sys- tem binders and their modification.
• Laempe & Mossner, which studied coremaking equip- ment suitable for volume production using silicate binder systems.
• The institute of foundry technology of TU (Technische Universität Bergakademie Freiberg) developed sand recla- mation and recycling.
• BMW, VW and Daimler’s nonferrous metalcasting facil- ity located in Mettingen, Germany, which carried out processing experiments and application. Based on intensive research and development, a new sili-
cate binder commenced production trials in 2006 to test the process feasibility and was soon put into volume production. It is now confirmed that for this new silicate binder, good results have been achieved in ecology, quality and economy. Tis research achievement marked a new era of applica- tion for silicate, especially in volume production in the auto industry. China’s FAW automotive group has introduced this technology for aluminium casting production. From production experiences, two principles need to be
followed to resolve the reclamation and recycling problem of silicate bonded sand: • The sand molds and cores must not be subjected to high temperature for too long a period. The water glass film around the sand grains cannot be allowed to lose bound water or combined water. More importantly, silicates cannot be allowed to fuse with the sand. At present, this silicate binder system is only suitable for aluminium or other low pouring-temperature alloy castings.
• After molds and cores have been produced, they can only be hardened by removing the free water in the binder. At present, this system is used only for making cores in Europe. The hardening method is to blow hot air, below 200C, through the core, causing it to be dehydrated and thus hardened. Furthermore, other materials should be prevented from coming into contact and reacting with silicate, so the used sand from shakeout will not contain any other reaction products. Silicate is a binder with good application prospects. How-
ever, at the moment it is used only for producing aluminium castings. For application in steel casting, shakeout, reclama- tion and recycling still present problems and need further
study and development. Alkaline phenolic resin—Alkaline phenolic resin is
粘结剂的应用早已呈现每况愈下的态势
近年来，出于清洁生产和环境保护的考虑，各国工业 国家的铸造行业再次将注意力转向各种无机粘结剂，其 中当然首先是硅酸盐类。应该说，对水硅酸盐粘结剂的 研究和应用又进入了一个崭新的阶段，当然，这方面的 研究工作还只是刚刚起步，来日方长。
近十多年来，德国的同行对硅酸盐类粘结剂进行了全 面而系统的研究、开发工作，力度非常之大，由许多知 名的单位分工合作，其中有： • ASK公司和HA公司等世界知名的粘结剂生产厂商， 从事硅酸盐系粘结剂及有关改性剂方面的研究、开 发工作；
• Laempe & Mossner公司，研制适用于用硅酸盐系 粘结剂、大批量自动化制芯的设备；
• TU矿业研究院铸造研究所负责旧砂再生、回用方面 的研究；
• BMW（宝马）公司、大众汽车公司和Diamler公司 位于Mettingen的轻合金铸造厂等生产企业从事工 艺试验和生产应用。
在大量研发工作的基础上， 2006年开始试生产，以 考核工艺的可行性，很快就正式在汽车工业大批量生产 中应用。现已确认：在生态、产品质量、经济等方面都 获得了很好的效益。这项成果，标志着硅酸盐粘结剂的 应用已经进入了一个崭新的纪元，其在汽车行业大批量 中的应用尤其值得重视。我国一汽公司最近已经引进了 这项技术，用于铝合金铸件的生产。
虽然未见报道与他们产品相关的具体技术内容，但 是，从许多生产厂家的情况介绍中，我们大致可以得 知，要解决硅酸盐粘结砂的再生、回用问题，必须遵循 以下两条原则。
（1）铸型或芯子不能经受太高温度的作用，不能使 水玻璃膜失去其中的牢固结合水和化合水，更不能使其 与砂粒熔合，目前，只宜用于生产铝合金铸件或某些浇 注温度更低的合金铸件。
（2）铸型、芯子制成后，只能借助于脱除自由水使 之硬化。目前，欧洲还只是用于制芯，采用的硬化方 法是在制芯后吹200℃以下的热空气使之脱水硬化，而 且，应该避免任何材料与硅酸盐发生反应，落砂得到的 旧砂中应不含任何反应产物。
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FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION May 2013
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