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Table 1. Chemical Composition of Blast Furnace Melt for Cast Pipes 表1 铸管用高炉铁水化学成分(%)


C 3.8-4.5 Si 0.8-1.5 Mn ≤0.4


ments. In addition, a blast furnace is tapped periodically, while foundry production is continuous. Since 2004, Qian’an Jintang Ductile Cast Iron Pipe Co.


Ltd., Qian’an City, Hebei Province, China, has tested the shortcut procedure technology with a 123-cu. m blast furnace on its two new casting lines for small and medium iron cast- ings and two centrifugal cast iron pipe production lines. The Chinese national policy of retaining blast fur-


naces for foundry production and constructing a foundry base provided the opportunity for the new technology. Jintang established a 1,500-acre foundry sector around the blast furnace. In the sector, all public facilities and the R&D platform are shared, with a centralized supply of electricity, water and heat and centralized recycling of wastewater, waste sand and slag. An economical pattern of recycling has been established for the blast furnace and the shortcut procedure (Fig. 1).


Shortcut Technology for Centrifugal Cast Ductile Iron Pipe


Centrifugally-cast ductile iron pipes are widely used,


especially in developed countries. The supply of high quality melt is essential for high quality pipe production. In order to reduce cost, investment and energy consump- tion and improve the quality of castings, metalcasting facilties are updating melting technology and installing new equipment. Currently, the melt typically comes from a blast furnace or cupola. The two most adopted methods are combining a blast furnace with a medium frequency induction furnace or a cupola with a medium frequency induction furnace. At Jintang, the composition and temperature of the


melt is strictly controlled, and a continuous supply must be guaranteed. Manganese, phosphorus, sulfur, titanium and chromium must be strictly controlled (Table 1). Te temperature control of the melt depends on the pipe


diameter. For example, the melt should be around 1,270- 1,440C for DN80 to DN800 cast pipes (Table 2). Centrifugal casting is a high-efficiency process that often encompasses multiple specifications of products


S ≤0.03 P ≤0.08 Ti ≤0.1 Cr ≤0.06


是高炉与铸造厂毗邻。由于目前高炉向大型化发展,高 炉的铁液产量远远超过铸造用铁液需求量;同时还存在 高炉间断出铁和铸造连续生产的矛盾。这些问题一定程 度上阻碍了短流程工艺的应用。


迁安市津唐球墨铸管有限公司自2004年开始,根据 自身条件,利用1台128m3高炉,配合新建的两条铸造 生产线和两条离心球墨铸铁管生产线,开始试验采用短 流程铸造工艺,在离心球墨铸铁管及普通中小型铸铁件 生产中取得成功。


国家保留专产铸造生铁高炉的政策和铸造生铁基地建 设,为实现短流程铸造工艺提供了保证。津唐公司依托 现有1,500亩厂区,建立起了以高炉为中心的铸造工业 园,园区内企业实行公共设施共享,共享研发平台,集 中供电、供水、供暖,并实行废水、废渣、废砂集中回 收处理,初步建立起了以专产铸造生铁高炉为中心,以 短流程铸造工艺为特色,废弃物循环再利用的绿色循环 经济模式,如下图所示。


一.短流程铸造工艺在球墨铸铁管生产中的应用


在世界各国尤其是经济发达国家, 离心铸造球墨铸铁 管得到了普遍应用。我国自20世纪80 年代引进这项生 产技术和设备以来, 离心球墨铸铁管的生产和应用也已 在逐步发展。合格的离心铸造球墨铸铁管的生产, 提供 高温优质铁水是其先决条件, 因此铁水的熔炼处理显得 十分关键。为了减少投资、降低成本、节约能源和提高 产品质量, 国内外的生产企业都在不断探索, 改进熔炼工 艺和设备。目前, 采用离心铸造工艺生产球墨铸铁管所 用铁水, 主要来自高炉或冲天炉, 且多选择高炉+中频感 应电炉、冲天炉+中频感应电炉的双联工艺。其中高炉 +中频感应电炉工艺,优势明显,前景广阔。


1.对所用铁水的要求 离心铸造球墨铸铁管的生产工艺较复杂且要求严格,


Table 2. Temperature Control of Pipes With Different Diameters (C) by Specification 表2 不同管径球墨铸铁管浇注温度(℃) Types 类型


Temperature of nodularizing ladle


球化包温度 Temperature of the sector ladle


扇形包温度 58 | FOUNDRY-PLANET.COM | MODERN CASTING | CHINA FOUNDRY ASSOCIATION Fall 2011


DN80-300mm 1,440-1,500


1,330-1,400


DN400-800mm 1,380-1,420


1,300-1,360


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