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An as-cast bainite ductile iron with excellent mechanical properties and wear resistance was fabricated by alloying and centrifugal casting method, and the alloyed chemical composition was optimized by using the thermodynamic software Thermo-Calc. By using optical microscopy, transmission electron microscopy, scanning electron microscopy, and X-ray diffraction, the microstructure of the as-fabricated bainite ductile cast iron was characterized pertinent to the elements distribution in matrix and features of ferrite and retained austenite. The results of mechanical properties test show that the hardness and compressive strength of this alloyed ductile iron are 52 HRC and 2,200 MPa, respectively. The as- cast bainite ductile iron possesses highly abrasive wear resistance and the reason can be ascribed to the solid solution of the elements Si, Ni, Cu, and Mn in the austenite and the formation of carbides of elements Cr and Mo. The strength of bainite ductile iron is increased by the acicular bainitic ferrite in the matrix. 相似文献
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探讨了在砂型连续冷却条件下,向球铁中同时添加cu、Ni、Mo等合金元素,获得以奥氏体 贝氏体为主的多相复合组织球铁;考察了在冷却条件一定的情况下,添加合金总量对其力学性能的影响.结果表明:当添加合金总量(质量分数)大于3.60%时,铸态球铁ob可以稳定在900 MPa以上;当添加合金总量达到3.95%时,铸态球铁具有最佳的综合力学性能;继续增加合金添加量,冲击韧度和伸长率将下降. 相似文献
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贝氏体—马氏体抗磨球墨铸铁热处理工艺的试验研究 总被引:2,自引:0,他引:2
试验研究了淬火介质、奥氏体化温度和回火温度对贝氏体-马氏体抗磨球墨铸铁组织与性能的影响。选择合理的热处理工艺,获得了优良的性能,洛氏硬度达50-55HRC,冲击韧度为8-15J/cm^2,φ80mm磨球冲击疲劳寿命(落球试验的跌落次数)达2万次以上。 相似文献
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Ranjan Kumar Dasgupta Dipak Kumar Mondal Ajit Kumar Chakrabarti Ashis Chandra Ganguli 《Journal of Materials Engineering and Performance》2012,21(8):1728-1736
The present investigation was carried out to study the effect of manganese and copper addition, singly as well as in combination, on the microstructure, micro-segregation, and mechanical properties of ductile irons. Alloy A (3.18C, 2.64Si, 0.45Mn), alloy B (3.35C, 2.51Si, 0.82Mn), alloy C (3.16C, 2.80Si, 1.08Mn, 0.56Cu), and alloy D (3.18C, 3.00Si, 1.04Mn, 1.13Cu) were melted and cast in the form of Y-block test pieces. The cast microstructures varied from ferrito-pearlitic in alloys A, B, and C to pearlitic in alloy D. However, on XRD analysis and SEM examination, the presence of martensite patches was also detected. There was a marginal decrease in nodule count in alloy B. In alloys C and D, nodule counts were higher, but the proportion of ferrite decreased drastically. Alloy D was found to be the strongest (UTS????800?MPa, El?=?5%) with alloys A and C coming next in strength; while alloy B was weakest of the four. The presence of martensite patches in association with pearlite appears to be responsible for low toughness of these alloys. Microprobe analysis shows some silicon segregation near the graphite nodules and practically little segregation of manganese. Elemental mapping by FE-SEM does not indicate any manganese segregation. 相似文献
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贝氏体相变与等温淬火球铁 总被引:1,自引:0,他引:1
详细介绍了贝氏体相变的特征及其分类。指出不同化学成分和不同等温温度时贝氏体相变产物的组织形态不同,铁素体是贝氏体中不可缺少的组成部分,以及碳化物的存在与否不是判断贝氏体的必要依据。研究了等温淬火球铁的相变过程,指出了对等温淬火球铁组织命名的看法。 相似文献
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连续冷却贝氏体球铁成分和工艺的研究 总被引:2,自引:1,他引:2
探讨了连续冷却的各工艺参数对含铬、钼、铜、锰、硼、铌等多元微量元素的合金球铁显微组织和强韧性能的影响,从而制订了获得贝氏体组织的新工艺,并以锤片、齿轮、杂质泵过流部件等为对象进行了生产验证,结果表明,采用该工艺可以稳定地获得贝氏体组织,其力学性能良好(硬度超过50HRC,冲击韧度超过10J·cm-2),经济效益显著。 相似文献
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研究了硅对铸态厚断面高韧性球墨铸铁组织及性能的影响。试验结果表明,硅主要分布于基体中,富集于奥氏体壳局部区域时,降低奥氏体壳的熔点,延长石墨自由生长的时间,造成石墨畸变。在铸件壁厚为100mm,树脂砂工艺条件下,硅含量为2.0%~2.5%时,石墨球化等级2~3级,球径等级6-7级,基体为铁素体。抗拉强度大于400MPa,伸长率大于20%,-20℃时的冲击韧度在16J/cm^2以上。硅含量达到2.9%时,易产生开花状石墨和碎块状石墨,铸件的性能严重下降。 相似文献
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