共查询到18条相似文献,搜索用时 765 毫秒
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用硅钡合金作孕育剂,并与相同条件下用铝孕育处理可锻铸铁进行比较,研究了钡对第一和第二阶段石墨化的影响。组织观察和性能测试结果表明:钡可促进第一和第二阶段石墨化过程,有利于获得铁素体基体;经硅钡孕育处理后铸铁组织中絮状石墨的外形趋于团球化,石墨的尺寸也有所减小,强度和塑性都有不同程度的提高。 相似文献
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用硅钡合金与75硅铁比较,研究了两种孕育剂对灰铸铁白口趋向,断面敏感性以及强度性能等的影响。结果表明:硅钡合金较75硅铁具有失效、白口趋向小、易获得A型石墨、断面敏感性小等优点,适合处理高牌号薄壁灰铸铁件。 相似文献
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钡硅铁孕育处理HT250的试验研究 总被引:1,自引:0,他引:1
用自制的硅钡合金与75硅铁相比较,研究了不同种类孕育剂对HT250石墨组织、白口趋向、断面敏感性以及强度性能等的影响。试验结果表明,硅钡合金较75硅铁具有长效、白口趋向小、易获得A型石墨、断面敏感性小等优点,适合处理高牌号薄壁灰铸铁件。 相似文献
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为避免因被孕育的铁液在浇包中停留时间过长而导致的孕育衰退,使铸件产生麻口和白口、降低铸件综合力学性能的现象的发生,通过用硅钡复合孕育剂取代75SiFe孕育剂孕育铁液,在相同生产工艺条件下,进行消除白口倾向作用的大小、抗孕育衰退的能力、力学性能对比、阶梯试块作壁厚敏感性试验、应力框铸造收缩应力试验等生产工艺性试验对比。结果表明,硅钡复合孕育剂孕育长效,衰退速率低,白口倾向小,石墨化能力强,改善了石墨形态,可明显增强铁液抗孕育衰退的能力,提高了铸件的综合力学性能。 相似文献
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介绍了4种不同类型的二次孕育剂对模拟尺寸为φ590 mm×800 mm的大断面球墨铸铁的组织及性能的影响。结果表明,二次孕育工艺对球铁尤其是大断面球铁的石墨及力学性能均有良好的改善作用;利用Si-Ba-Ca孕育剂进行孕育处理后再添加0.15%的该孕育剂作为二次孕育处理,可改善铸件组织及提高铸件力学性能;S-O孕育剂和Si-Ba-Ca孕育剂的效果相对较好,模拟铸件中碎块状石墨区域明显减少、石墨球形态圆整、球化率较高,还可以有效避免孕育衰退,使铸件获得较好的微观组织和最佳的综合力学性能。 相似文献
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本文论述了普通硅铁与四种不同成份的硅钡钙复合孕育剂的孕育效果。试验与生产表明,成份(%)为Si55~60、Ba4~6、Ca5~7、Mn<2、Al1~3的硅钡钙复合孕育剂的孕育效果显著,且具有较强的抗衰退能力。用此孕育剂孕育处理HT30—54原铁水,可获得HT35—61铸铁,且铸铁的激冷倾向小,壁厚敏感性小。 相似文献
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高碳当量灰铸铁孕育剂的试验与应用 总被引:1,自引:0,他引:1
提出了生产电机端盖薄壁灰铁件对孕育剂的要求。在生产条件下进行试验,确定硅钡稀土合金是生产此类铸件效果较好的孕育剂,该孕育剂在高砂型硬度、垂直分型、高碳当量及铸件壁薄等条件下,具有减少白口倾向、降低铸件硬度、加入量少、抗孕育衰退能力强等特点,是高碳当量灰铸铁孕育效果良好的孕育剂。 相似文献
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Mohd Nadeem Bhat D. M. Afzal Khan K. K. Singh 《International Journal of Cast Metals Research》2018,31(5):261-268
In this study, the effect of inoculant composition and nodularisation treatment temperature on recalescence temperature (TER) and undercooling temperature (TEU) in SG iron has been studied by using thermal analysis. 0·1, 0·2 and 0·3 wt-% of three types of inoculants Ca,Ce,Al–FeSi, Ca,Sr,Al–FeSi and Ca,Ba,Al–FeSi were used as so called stream inoculation. Ca,Ce,Al–FeSi was found to be the most potent one in reducing both recalescence (?T r ) and eutectic undercooling (?T). The nodule count has also been found higher in Ca,Ce,Al–FeSi inoculated SG iron samples compared to other two inoculants. It has been observed that higher the nodule count lower is the ?T r and ?T and vice versa. The recalescence and shrinkage relationship of 24 heats of differential case castings has been established; it was observed that the number of castings containing shrinkage in respective heats increase as the recalescence and nodularisation treatment temperature increases. 相似文献
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研究了压力成型孕育块的熔解特性及孕育剂组成。结果表明,在75硅铁孕育块含有适量的Bi和冰晶石并具有合适的形状时,可以减小孕育滞后,提高孕育均匀性,满足生产薄壁铸态铁素体球墨铸铁件的孕育要求。 相似文献
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通过对几种不同的型内孕育块成型工艺特点的分析对比,提出了压力成型型内孕育块工艺,并对其成型参数作了介绍。试验表明,采用压力成型的孕育块具有良好的孕育效果,满足薄壁铸态铁索体球铁的生产要求。 相似文献
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介绍了生产厚大球铁件的原材料和化学成分选择原则;认为采用合适的孕育剂和球化剂,进行多频次、大孕育量孕育是确保厚大球铁件质量的重要手段;为稳定生产高质量厚大球铁件,特别推荐应用预处理技术和热分析技术,并介绍了预处理提高铁液抗衰退能力和热分析量化铁液冶金质量的原理。 相似文献
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Iulian Riposan Stelian Stan Valentin Uta Ion Stefan 《Journal of Materials Engineering and Performance》2017,26(9):4217-4226
Inoculation is one of the most important metallurgical treatments applied to the molten cast iron immediately prior to casting, to promote solidification without excessive eutectic undercooling, which favors carbides formation usually with undesirable graphite morphologies. The paper focused on the separate addition of an inoculant enhancer alloy [S, O, oxy-sulfides forming elements] with a conventional Ca-FeSi alloy, in the production of gray and ductile cast irons. Carbides formation tendency decreased with improved graphite characteristics as an effect of the [Ca-FeSi + Enhancer] inoculation combination, when compared to other Ca/Ca, Ba/Ca, RE-FeSi alloy treatments. Adding an inoculant enhancer greatly enhances inoculation, lowers inoculant consumption up to 50% or more and avoids the need to use more costly inoculants, such as a rare earth bearing alloy. The Inoculation Specific Factor [ISF] was developed as a means to more realistically measure inoculant treatment efficiency. It compares the ratio between the improved characteristic level and total inoculant consumption for this effect. Addition of any of the commercial inoculants plus the inoculant enhancer offered outstanding inoculation power [increased ISF] even at higher solidification cooling rates, even though the total enhancer addition was at a small fraction of the amount of commercial inoculant used. 相似文献