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铌对灰铸铁机械性能的影响 总被引:6,自引:0,他引:6
研究了铌对灰铸铁机械性能的影响及其强化机理;试验表明,铌在提高铸铁耐磨性能的同时又能显著地提高铸铁的强度性能,改善铸铁的韧性;当含铌量为015%~04%时,铸铁机械性能提高一个牌号 相似文献
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探讨了普通灰铸铁利用铸造余热直接进行等温淬火后的组织与性能,结果表明:普通灰铸铁不需要再额外添加合金元素,通过铸造预热等温淬火,就可以使灰铸铁基体获得下贝氏体组织,从而使灰铸铁的硬度和抗拉强度均有一定幅度提高。 相似文献
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Sn作为一种合金化元素,在灰铸铁中既可强烈促进珠光体的生成,又可细化珠光体.在实际生产中,由于某些生铁中含有过量的Sn,铸件易产生裂纹或显微裂纹,导致铸件报废.制备了不同Sn含量的铸件试样,并测定了其抗拉和抗弯强度,用金相显微镜观察不同Sn含量对铸件的石墨形态和基体组织的影响,同时详细考察了其铸造性能.结果表明:适量的Sn会促进珠光体基体的形成、细化共晶团,而对石墨的组织和形态无明显的不良影响.同时微量的Sn溶于奥氏体中,降低了发生先共析铁素体和珠光体的温度范围,使收缩率降低.但过量的Sn增加碳化物和磷共晶的数量,同时使灰铸铁的白口宽度增加,使铸件产生硬脆性,从而导致热裂和冷裂,这是铸件产生裂纹的主要原因.在生产中,应采取措施使铸铁中Sn含量控制在0.102%以下,并结合孕育处理等措施改善铸件的组织,提高力学性能. 相似文献
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Aravind Vadiraj Shashank Tiwari 《Journal of Materials Engineering and Performance》2014,23(8):3001-3006
Influence of Si on mechanical and wear properties of Al-alloyed gray cast iron has been investigated in this work. The Si content is varied from 1.27 to 2.1% in five different alloys with nearly 2% Al additions. Alloy with 2.1% Si and 1.9% Al shows maximum ferrite matrix with highest flake volume (17.3%). It also has the lowest hardness and strength. Rest of the alloys with Si content equal to or less than 1.7% and 2% Al content shows maximum pearlite matrix with higher hardness and strength. They have also shown a tendency for oxide formation and reduced wear during sliding probably due to higher friction heat and lower heat dissipation tendency due to lower flake volume and Al addition which reduces thermal conductivity of the matrix. The same oxide layer was not evident in alloy with 2.1% Si and 1.9% Al alloy having the highest flake volume (17.3%). 相似文献
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研究了亚温淬火和常规等温淬火对球墨铸铁汽缸套组织及性能的影响。结果表明,亚温淬火后,球墨铸铁的组织为下贝氏体+富铜的残余奥氏体+块状铁素体+少量含铌碳化物,硬度不小于300 HB;常规等温淬火后,球墨铸铁的组织为下贝氏体+富铜的残余奥氏体+少量含铌碳化物,硬度不小于350 HB。与常规等温淬火汽缸套相比,亚温淬火汽缸套的抗拉强度、硬度有所降低,弹性模量、线膨胀系数、导热系数基本不变,断后伸长率有所增加。在润滑状态及负载恒定的情况下,两种淬火工艺的汽缸套的摩擦系数均随转速提高而降低,但与常规等温淬火相比,亚温淬火汽缸套的摩擦系数更小。亚温淬火汽缸套的加工性能显著改善,同等条件下加工数量为常规等温淬火汽缸套的5倍以上。 相似文献
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J. P. Lai Q. L. Pan Z. B. Wang H. R. Cui X. D. Wang Z. Z. Gao 《Journal of Materials Engineering and Performance》2017,26(10):4667-4675
The effect of destabilization temperature on the microstructure and impact toughness of high chromium cast iron was investigated. The result showed that the microhardness of matrix decreased from 860 to 332 HV with the increase of destabilization temperature from 950 to 1100 °C. The impact toughness of the alloy increased from 5.3 to 8.1 J/cm2 with the increase of destabilization temperature from 950 to 1050 °C, while it decreased with further increase of destabilization temperature. The former change of impact toughness was found to be due to the increase in volume fraction of retained austenite from 12.6 to 56.5%, whereas the latter was attributed to the increase of carbon content in retained austenite by analysis of fracture morphologies. The wear resistance decreased with the increase of destabilized temperature from 950 to 1050 °C and increased only slightly for the temperature from 1050 to 1100 °C. 相似文献
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灰口铸铁热变形后的组织与性能 总被引:1,自引:0,他引:1
采用包覆压缩工艺在Gleeble3500热模拟试验机上实现了灰口铸铁的大塑性变形。热变形试样在石墨化退火后用光学显微镜和图像分析仪观察了显微组织和石墨形态,采用显微硬度测试以及小试样拉伸方法研究了压下量对灰口铸铁力学性能的影响.用扫描电镜观察了拉伸断口微观形貌。结果表明,灰口铸铁大塑性变形后,石墨片趋于平行分布,试样的显微硬度、拉伸强度和伸长率均有不同程度的提高,经过80%热变形的试样其显微硬度增加到217HV,拉抗强度提高到249MPa,伸长率增加到5.2%;扫描电镜观察表明,拉伸断口有分层特征。 相似文献
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本文以A3废钢为主要原料,添加Si、Mn、Cr和一种廉价的金属等多种合金元素,加入少量Mo、稀土进行微合金化和变质处理,在中频炉冶炼、潮模砂型的条件下,制得10 mm×10 mm×55 mm无缺口冲击试样.经热处理后,获得了以准贝氏体为基体综合性能优良的合金钢.该钢经过奥氏体化后空冷,再经回火处理,分别测试了空冷、回火处理后试样的洛氏硬度、冲击韧性,并在Olympus和扫描电子显微镜(SEM)下观察了其组织形态与断口形貌.试验结果表明,试样经920 ℃保温1 h奥氏体化后空冷、300 ℃保温2 h回火后得到较好的硬度与冲击韧性的匹配,硬度达到HRC 34,冲击韧性高于240 J/cm2,金相组织以准贝氏体为主,含有少量的残余奥氏体.实验证明该钢是一种热处理工艺简便、成本低、可以代替调质钢、提高经济效益的新型钢种. 相似文献
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等温淬火温度对奥贝球墨铸铁力学性能的影响 总被引:2,自引:1,他引:1
研究表明,随着等温淬火温度的升高,奥贝球墨铸铁的抗拉强度和硬度均呈下降趋势,伸长率呈上升趋势,而冲击韧度则随等温淬火温度的升高先增后减,有峰值出现。 相似文献