共查询到19条相似文献,搜索用时 140 毫秒
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研究了奥贝球铁,下贝球铁及与其基体组织相同的钢的滑动磨损性能。实验结果表明:在一定条件下,石墨对等温淬火球铁耐磨尾无补而有损,由于奥贝球铁的转折载荷随摩擦速度的提高而增大,当转速为980r/min,载荷〉68.6N,等温淬火球铁的耐磨性优于钢。 相似文献
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关于奥贝球铁及其微观组织术语的探讨—对ADI(AustemperedDuctileIron)我们需要一个正确的中文术语 总被引:13,自引:2,他引:13
论述了等温淬火球铁的工艺及其微观组织。分析了其微观组织与钢中贝氏体的区别。指出ADI(Austempered Ductile Iron)奥贝球铁是一个恰当的术语。对这种新铸铁,我们需要一个正确的中文术语:奥铁球铁或者称奥氏体等温淬火球铁。 相似文献
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研究了由三种热处理工艺获得的全贝氏体等温淬火球的机械性能、组织状态及切削加工性能和耐磨性能。结果表明:这种球铁的强度和硬度和奥贝球的相当,耐磨性略低于奥贝球铁;而塑性、韧性及切削加工性能与珠光体球铁的相当。这种球铁的基体组织为上贝氏体加部分粒状贝氏体。 相似文献
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介绍奥贝球铁的特性和使用价值,阐述主要几种合金元素对奥贝球铁热处理和力学性能的影响,分析了奥贝球铁等温淬火热处理规范及工艺过程,对具有高强度、高韧度的奥贝球铁材料的工业应用方面的情况作了介绍。 相似文献
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针对某厂汽车发动机奥贝球铁齿轮材料,研究了等温淬火工艺对奥贝球铁组织和性能的影响。结果表明:经880℃奥氏体化+320℃等温淬火处理,可获得上贝氏体/下贝氏体的混合组织。该组织具有优良的综合机械性能,满足了汽车发动机齿轮的技术要求。 相似文献
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试验在球铁化学成分、熔炼、球化孕育处理和等温淬火工艺完全相同条件下,研究了等淬前试样的不同基体组织和等淬后回火处理对奥贝球铁冲击值的影响。结果表明,淬火前铸态混合基体组织和等淬后回火处理有益于奥贝球铁冲击韧度的提高 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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A computer-controlled system for measuring electrical resistance has been developed and used to study the isothermal transformation
of austenite in a ductile iron (3.31 % C, 3.12 % Si, 0.22 % Mn, 0.55 % Cu). The ability of the technique to follow the isothermal
decomposition of austenite was established by measurements on an AISI4340 steel. The times at which the austenite decomposed
to primary ferrite, pearlite, and bainite were accurately detected. In the ductile iron, the formation of pearlite and of
bainite was easily detected, and an isothermal transformation diagram was constructed from the results. The temperature range
for the formation of bainite is especially important in producing austempered ductile iron (ADI) and was mapped. An initial
stage of decomposition of austenite to ferrite and high-carbon austenite is followed by a time delay; then the high-carbon
austenite decomposes to bainite. The formation of ADI requires austempering to a structure of ferrite and high-carbon austenite,
then quenching to retain this structure, thus avoiding the formation of bainite. This is achieved by isothermal transformation
into the time-delay region. For the ductile iron studied here, this time region was about 2.6 h at 400 °C and increased to
277 h at 300 °C. 相似文献
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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 ascast 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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奥氏体—贝氏体合金球铁磨球的研制与应用 总被引:1,自引:0,他引:1
研究了一种新型磨球材质———奥贝合金球铁,采用合金化和等温淬火处理,可以获得下贝氏体、残余奥氏体、少量马氏体基体组织的球铁。该材质的磨球在不同工况下装机考核。结果表明,其耐磨性明显优于低合金球铁和锻钢。它的推广应用具有显著的综合效益。 相似文献
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团球状共晶体奥氏体-贝氏体钢抗冲击磨料磨损行为 总被引:1,自引:0,他引:1
采用TEM,SEM;电子探针和 MDL-10型动载磨料磨损实验机研究 Mg-Ce-AI复合变质团球状共晶体奥-贝钢(简称ABNE钢)复相组织的形成及抗冲击磨料磨损行为结果表明,钢中贝氏体组织由板条铁素体与残余奥氏体组成,团球状共晶体是(Fe, Mn)3C和奥氏体两相伪共晶组织 ABNE钢在中、低冲击工况下耐磨性优于奥-贝钢、奥-贝球铁、团球状碳化物中锰钢,其原因与国球状共晶体可有效地减轻磨料的侵入深度和阻碍微切削作用,以及磨损表面形成大量纳米晶粒和非晶态组织。在亚表层存在形变马氏体与形变贝氏体组织有关 相似文献
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A detailed review of wear resistance properties of austempered ductile iron (ADI) was undertaken to examine the potential
applications of this material for wear parts, as an alternative to steels, alloyed and white irons, bronzes, and other competitive
materials. Two modes of wear were studied: adhesive (frictional) dry sliding and abrasive wear. In the rotating dry sliding
tests, wear behavior of the base material (a stationary block) was considered in relationship to countersurface (steel shaft)
wear. In this wear mode, the wear rate of ADI was only one-fourth that of pearlitic ductile iron (DI) grade 100-70-03; the
wear rates of aluminum bronze and leaded-tin bronze, respectively, were 3.7 and 3.3 times greater than that of ADI. Only quenched
DI with a fully martensitic matrix slightly outperformed ADI. No significant difference was observed in the wear of steel
shafts running against ADI and quenched DI. The excellent wear performance of ADI and its countersurface, combined with their
relatively low friction coefficient, indicate potential for dry sliding wear applications. In the abrasive wear mode, the
wear rate of ADI was comparable to that of alloyed hardened AISI 4340 steel, and approximately one-half that of hardened medium-carbon
AISI 1050 steel and of white and alloyed cast irons. The excellent wear resistance of ADI may be attributed to the strain-affected
transformation of high-carbon austenite to martensite that takes place in the surface layer during the wear tests. 相似文献
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Uma Batra Nimish Batra J. D. Sharma 《Journal of Materials Engineering and Performance》2013,22(4):1136-1142
An investigation was carried out to examine the influence of structural and mechanical properties on wear behavior of austempered ductile iron (ADI). Ductile iron (DI) samples were austenitized at 900 °C for 60 min and subsequently austempered for 60 min at three temperatures: 270, 330, and 380 °C. Microstructures of the as-cast DI and ADIs were characterized using optical and scanning microscopy, respectively. The structural parameters, volume fraction of austenite, carbon content of austenite, and ferrite particle size were determined using x-ray diffraction technique. Mechanical properties including Vicker’s hardness, 0.2% proof strength, ultimate tensile strength, ductility, and strain hardening coefficient were determined. Wear tests were carried out under dry sliding conditions using pin-on-disk machine with a linear speed of 2.4 m/s. Normal load and sliding distance were 45 N and 1.7 × 104 m, respectively. ADI developed at higher austempering temperature has large amounts of austenite, which contribute toward improvement in the wear resistance through stress-induced martensitic transformation, and strain hardening of austenite. Wear rate was found to depend on 0.2% proof strength, ductility, austenite content, and its carbon content. Study of worn surfaces and nature of wear debris revealed that the fine ausferrite structure in ADIs undergoes oxidational wear, but the coarse ausferrite structure undergoes adhesion, delamination, and mild abrasion too. 相似文献
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利用MM-200摩擦磨损试验机,在油润滑条件下对含碳化物奥铁体球墨铸铁(CADI)表面离子渗S层的摩擦学性能进行了研究,并与W6Mo5Cr4V2高速工具钢的磨损进行对比,利用扫描电子显微镜观察磨痕宽度和磨损形貌。研究结果表明:载荷对渗S的CADI试样耐磨性影响较大,当载荷小于300 N时,磨损失重较小;当载荷超过300 N时,随着载荷的增加,其磨损失重显著增加;在50 N的载荷作用下,渗S的CADI耐磨性与高速钢相当,也就是说,当施加载荷较小时,渗S的CADI可以替代高速钢制作压缩机滑片。 相似文献