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研究了采用增碳工艺法生产球墨铸铁时K/Na-RE复合变质处理的作用。发现:合理使用K/Na-RE复合变质剂能够优化增碳处理工艺,改善铁液质量,显著提高铁液的石墨形核状态,从而增加石墨球的数量,细化石墨球和基体组织。 相似文献
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简单介绍了增碳剂的类型及选用原则;对影响增碳剂增碳率和增碳作用的因素进行了分析,指出在球墨铸铁生产中,应用增碳及铁液预处理工艺,可减少铁液杂质元素和有害元素的含量,降低炉料遗传性影响,增加石墨球数,改善球化率,提高材料的力学性能。 相似文献
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合成铸铁的生产及应用 总被引:1,自引:0,他引:1
熔炼合成铸铁,由于废钢加入量大,增碳技术成为其生产的关键技术。对合成铸铁的增碳原理、铸铁熔炼工艺进行了分析。结果表明,采用晶体石墨增碳剂,电炉熔炼合成铸铁的增碳速度明显高于非石墨增碳剂;且晶体石墨增碳剂可作为石墨的外来晶核,促进细片状A型石墨的形成,铁液白口倾向小,力学性能提高。 相似文献
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采用中频感应电炉熔炼生产灰铸铁机车制动摩擦圈,原采用HT300配料方案适当增加生铁比例,检测发现化学成分和抗拉强度符合顾客规范要求,但铸件本体硬度偏低.后采用合成铸铁熔炼工艺,为提高增碳剂的吸收率,提高了熔炼温度,同时为了提高炉前检测的准确性,取样温度提高20 ℃;结果显示,铸件本体金相组织为A型石墨4级、超过95%的珠光体及少量铁素体,抗拉强度和本体硬度均达到要求.经计算,应用合成铸铁熔炼工艺,每吨铁液节约炉料成本185.9元,每月 500件铸件可节约成本14 624.13元. 相似文献
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介绍感应电炉熔炼使用增碳剂的小知识,说明悬浮的石墨微粒有利于生成石墨核心,防止铸铁过冷和白口化;选用粒度恰当的增碳剂可以缩短增碳时间,改善增碳效果;铁液硅量、硫量高会使增碳速度变慢。介绍增碳剂的选择及加入方法。 相似文献
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实际生产条件下,对球铁生产工艺进行正交设计优化,对其试样进行金相组织观察和力学性能测试。试验结果表明,铁液在相同的出炉温度条件下,球化处理时间延长,石墨球长大且数量减少;在相同的球化处理时间条件下,铁液出炉温度的提高,也使石墨球变大数量减少;在相同的浇注条件下,铁液出炉温度高,球化处理时间长,同样使石墨球长大且数量减少;石墨球的长大且数量减少,对强度和硬度的变化不明显,而冲击韧性、断面收缩率和延伸率有所下降;确定最佳的工艺参数为铁液出炉温度为1525℃,球化处理时间为2min,浇注温度为1400℃。 相似文献
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SHU Xin-fu SHU Rui CHANG Dian-cun ZHANG Xiao-long ZHU Yan-dong LI Ling-fang LI Yu-zhong 《中国铸造》2005,2(4)
1 Introduction Ductile cast iron can be got after the molten iron in either eutectic or hypereutectic compositions modified by RE-Mg alloy or treated by enough inoculation and heat treatment, since the birth of ductile cast iron. During the development of ordinary ductile cast iron, the content of carbon is never lower than 2.0%, the low carbon ductile iron that is not treated by heat treatment and mod- ified by the inoculation alloy mainly composed of anti- spherical surface active elements … 相似文献
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本文制定了针状贝氏体球铁离心复合轧辊的生产工艺.通过该工艺实现了针状贝氏体球铁轧辊工作层和辊芯材料的双金属复合,从而获得了不同的组织和力学性能,满足了轧辊的工作要求,延长了轧辊的使用寿命. 相似文献
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Bingxu Wang Gary Barber Xichen Sun Michael Shaw Phil Seaton 《Journal of Materials Engineering and Performance》2017,26(5):2095-2101
Controlling the amount of retained austenite is a concern in austempered ductile iron formation. Retained austenite has a strong influence on austempered ductile iron properties, such as hardness and wear resistance. In this research, the characteristics of the transformation of retained austenite were investigated as a function of the number of tempering cycles. The hardness of the austempered ductile iron samples was measured, and the specific amount of retained austenite was analyzed by x-ray diffraction (XRD). Wear tests were conducted on a ball-on-flat sliding fixture. The tempering process was found to have no effect on the hardness of the austempered ductile iron samples. This may be due to retained austenite being partially converted into brittle quenched martensite during the tempering process. However, tougher tempered martensite was also formed from existing martensite. The two effects seemed to offset each other, and no significant differences occurred in overall hardness. XRD analysis showed that under the same austempering temperature and holding time, the amount of retained austenite decreased with additional tempering cycles. Also, with the same holding time and tempering cycles, less retained austenite was contained in the matrix at higher austempering temperatures. This was due to more high carbon content austenite and needle-like ferrite being present in the austempered ductile iron matrix. In addition, tempered austempered ductile iron exhibited significantly higher wear resistance as compared to traditionally treated ductile iron. 相似文献
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为生产高强度厚大断面球墨铸铁件,对熔炼原材料、铁液化学成分和球化孕育处理技术进行了分析,确定了球铁熔炼工艺的主要控制要素,采用高温正火热处理工艺保证材料均匀一致的基体组织。试制阶梯试块的力学性能和显微组织均符合技术要求,从而保证高强度厚大断面球墨铸铁件的正常生产。 相似文献
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