奥贝球铁材料接触疲劳强度的研究

奥贝球铁材料的弹性模量比钢小，因而奥贝球铁齿轮工作时受到的表面接触应力比钢齿轮小。奥贝球铁材料的接触疲劳应力可达1426MPa以上，高于280hp柴油机齿轮的接触应力，因此用奥贝球铁代替调质氮化钢生产280hp柴油机齿轮是完全可能的。     

350℃-Thermal Stability of Austempered Ductile Iron

The thermal stability of an ADI has been studied by isothermal aging at 350℃ for 150 hours, measuring the amount of retained austenite and its carbon content by X-ray diffractometry. The influence of different austempering treatments, carried out at temperatures between 300 and 450℃ (300, 330, 360, 410 and 450℃) and holding times between15 and 60 minutes (15, 30, 45, 60), was considered. Thermal stability depends on whether austempering temperature is higher or lower than the ageing one. Thermal stability increases by increasing austempering temperatures, from 300° to410℃. Samples treated at 410° and 450° show a lower austenite decomposition than samples at 300-330-360℃. A drop in stability is shown by increasing the austempering temperature from 410° to 450℃. The results have been interpreted on the basis of the austenite stability out of the processing window, which in turn depends on the austempering parameters.     

循环热处理和合金化对ADI性能的影响

研究了循环热处理和合金元素铜、镍及钼对ADI性能的影响。结果表明:加入铜0.8%、镍0.8%和钼0.3%的试样,在等温淬火前进行如下处理:在910℃保温3 min,降温至790℃保温25 min后机油淬火,晶粒尺寸比传统等温淬火方法的晶粒尺寸显著细化,抗拉强度和伸长率分别由原来的995 MPa,7.4%,提高到1 185 MPa,9.2%,分别提高19.1%,24.3%。     

高阶紧致差分与ADI结合的器件模拟方法

采用AD I与高阶紧致差分相结合的方法计算大型非对称稀疏矩阵,并实现了该算法在半导体器件模拟中的应用。数值计算表明,这种方法可以降低方程的迭代次数约35%,并明显减少方程的求解时间。     

原始组织对等淬球铁组织与性能的影响

研究了原始基体组织分别为铁素体和珠光体的球铁等淬后显微组织与性能的差别,结果表明：原始组织为珠光体基体的球铁,等淬后其显微组织中的白亮区较多,硬度值较高,而冲击韧度略低。     

欧洲北美ADI的最新进展

介绍了国外ADI的最新进展,一些研究发展趋势,ADI产品在机械行业的分布情况,ADI专业热处理厂和ADI重要生产厂的发展,CADI的最新进展,以及ADI生产的计算机数学模型。     

奥贝球铁的生产工艺

奥贝球铁具有很多优点,在各个领域中广泛应用。其生产技术尤其受到重视。详细叙述了奥贝球铁的各种生产方式,包括传统的等温淬火工艺,分级冷却工艺,连续冷却工艺和铸态、准铸态奥贝球铁生产工艺。     

芬兰的铸造业现状对中国奥贝球铁(ADI)产业化的思考

结合对芬兰铸造企业生产情况的实地考察，介绍芬兰铸造业的生产现状及技术水平，进而分析中国奥贝球铁(ADI)生产中存在的差距，并提出一些建议。     

Multilevel difference schemes for the heat conduction equation and its application to the dirichlet problem in two and three dimensions

In this paper we have discussed a general method of deriving high order multilevel schemes for the heat conduction equation in higher dimensions. The application of the three level parabolic schemes for the solution of the steady state Dirichlet problem in two and three dimensions is discussed by introducing two parameters. The error bounds given by Hadjidimos are further refined which drastically reduces the theoretical estimate of the number of iteration cycles required for a given accuracy η. We have also defined a new set of iteration parameters. A numerical example is computed and it is seen that the present methods produce accurate results.     

奥贝球铁齿轮在柴油机上的应用研究

研究了不同等温温度及Mn、Si、Cu、Mo对奥贝球铁组织和力学性能的影响,讨论了奥贝球铁加工硬化对机加工性能的影响。同时,奥贝球铁齿轮代替40Cr调质钢齿轮进行装机试验,对降噪声和耐磨性进行了测试。结果表明,奥贝球铁齿轮与40Cr调质钢齿轮相比,力学性能高,柴油机整机噪声下降1.92dB,齿轮侧噪声下降5.3dB,奥贝球铁齿轮经过45h磨合后,在标定工况下连续运转200h,齿轮无异常磨损,齿轮间隙离极限间隙还有0.13mm的余量,所以其摩擦磨损性能合格,所生产的奥贝球铁齿轮满足设计使用要求。