等温淬火球墨铸铁的滑动磨损

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性无补而有损。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 >6 8 6N时 ,等温淬火球铁的耐磨性优于钢     

Wear Performance of Cu-Alloyed Austempered Ductile Iron

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.     

奥贝球铁磨粒磨损性能的研究

奥贝球铁磨粒磨损性能的研究郭新立，孟祥康，刘治国，董鄂（南京大学）（南京理工大学）奥贝球铁是新一代的球墨铸铁，与普通球铁相比，奥贝球铁具有较高的强度、韧性、抗点蚀疲劳、弯曲疲劳和耐磨性能，被视为７０年代以来铸铁冶金的重大突破￣［１、４］。其应用目标之...     

等温淬火工艺对ADI耐磨性的影响

研究了等温淬火工艺对ADI耐磨性的影响。结果表明：当等温温度在260～380℃时,随着等温淬火温度的升高,耐磨性逐渐降低;360℃等温淬火时,耐磨性最差;继续升高等温淬火温度,耐磨性又有升高的趋势;当等温时间在30～120min,随着等温淬火时间的增加,耐磨性逐渐降低;等温淬火60min时,耐磨性最差;等温淬火时间继续延长,耐磨性又有升高的趋势。     

含碳化物奥铁体球墨铸铁渗S层的耐磨性研究

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。     

Fundamental Wear Mechanisms when Machining Austempered Ductile Iron (ADI)

Austempered Ductile Iron (ADI) is characterised by improved mechanical properties but low machinability compared to conventional ductile iron materials and steels of similar strengths. The mechanical properties of ADI are achieved by a very fine austenitic-ferritic microstructure. However this unusual microstructure significantly affects mechanical and thermal machining properties. A keen understanding for the interactions of microstructure, chip formation, machining properties, cutting material and wear mechanisms is essential for the optimisation of the cutting process. This paper describes material and machining investigations as well as cutting simulations to reveal the wear mechanisms being responsible for the low machinability of ADI.     

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。     

等温淬火球铁热处理

本文简要地介绍了等温淬火球铁的机械性能,详细地分析了球铁等温淬火的工艺过程,并展望了这种材料广阔的生产应用前景.     

奥贝球铁齿轮的等温淬火热处理

运用正交试验法对奥贝球铁生产拖拉机最终传动从动齿轮的热处理工艺进行了优化试验。分析了主要合金元素的作用 ,着重探讨了热处理工艺参数对奥贝球铁力学性能的影响 ,并对该材料的加工硬化能力进行了研究。试验结果表明 ,该奥贝球铁齿轮的优化热处理工艺为 :在 90 0℃奥氏体化保温 2h ,再进行 2 90℃× 1 5h等温淬火。在此工艺条件下可以得到以下贝氏体 +残留奥氏体为基体的金相组织 ,该组织具有较好的加工硬化性能。     

Austempered Ductile Iron—Processing and Properties

Recent research on austempered ductile irons (ADI) has been reviewed. The physical metallurgy of the austempering reaction and the important effects of alloying elements are discussed, along with an analysis of research results from the perspectives of ADI foundry and heat treatment process control and quality assurance. Both the existing database of ADI mechanical properties and progress made toward the specification of various ADI grades worldwide have been summarised. Although many fundamental questions remain regarding microstructure/property/processing relationships for the new and metallurgically complex family of ADI materials, foundry processing and heat treatment guidelines have been established for the successful production of ADI. Casting quality requirements are high due to the demanding combination of strength and toughness desired for ADI and to ensure consistent heat-treatment response during austempering.     

奥贝球铁的命名方式

介绍和总结了奥贝球铁的不同命名方式。指出了等温淬火球铁（ADI）、奥铁球铁（Ausferrite）、贝氏体球铁等几种名称，并对其作了进一步理解和认识，可为有关方面的研究提供参考依据。     

等温淬火球铁在铁道车辆耐磨件上的应用研究

考虑到等温淬火球铁具有强度高、韧性好、出色的耐磨性等优点，根据铁道车辆斜楔和衬套配件的服役要求，对等温淬火球铁和传统的金属材料进行了大量摩擦磨损性能比较试验，结果表明，等温淬火球铁斜楔和衬套具有比传统材料高得多的耐磨性，特别是等温淬火球铁斜楔的使用寿命是以往ZG230-450斜楔的6～10倍。因此，等温淬火球铁斜楔和衬套件已在我国铁路车辆上得到了广泛应用。     

奥-贝球铁焊缝的组织与力学性能

用Ｘ射线衍射仪，光学显微镜和电子显微镜，系统地研究了球铁焊缝金属等温贝氏体转变过程，等温温度等温时间为焊缝组织与力学性能的影响。研究结果表明，球铁焊缝金属贝氏体相变快，等温时间在１５－２４０ｍｉｎ范围内焊缝基体组织主要为贝氏体铁素体和残工体且具有高的综合力学性能。     

Material-related aspects of the machinability of Austempered Ductile Iron

The exceptional properties of Austempered Ductile Iron (ADI) are widely known and can be ascribed to its austenitic-ferritic microstructure. Strain hardening of this material is exceptional and an advantage for many applications where high wear resistance is required, as well as the extraordinary combination of ductility and tensile strength. One reason which restricts the introduction of this material in practical applications is its poor machinability. This paper describes the material-sided influences on machinability, especially on the acting wear mechanism. The heat treatment factor austempering time, ADI grade and the alloying elements nickel and molybdenum are varied and investigated in external longitudinal turning operations.     

奥-贝球铁的铸造原理及研究进展

奥-贝球铁具有高强度、高韧性、良好的耐磨性、耐热性、耐蚀性以及优良的铸造性能等特点,本文中概述了奥-贝球铁的铸造原理,详细介绍了碳、硅、锰、硫、磷、钼、镍、铜、钒、铌等合金元素及热处理工艺对奥-贝球铁性能的影响.并简要介绍了第四届国际奥-贝球铁学术会议的内容,对国内外奥-贝球铁的研究及生产应用作了综述,最后展望了奥-贝球铁的应用前景.     

等温淬火球铁(ADI)的机械加工性能

等温淬火球铁(ADI)对工程界来说是一种相对较新的材料。其独特的金属基体显微组织奥铁体,即针状铁素体和充分反应的、热力学稳定的、力学上也稳定的,高碳奥氏体的混和组织,使其具有比普通球铁高得多的强度和韧性。然而,高强度、高硬度和高韧性使等淬球铁在机加工时切削刃口受到更高的应力,造成一定困难。考虑了等淬球铁特有的金属基体组织和力学性能,选择了合适的刀具,调整和优化了刀具及加工参数,等淬球铁完全可以成功地进行机加工,从而可以扩大等淬球铁的应用和进一步开拓等淬球铁的潜力。笔者论述了等淬球铁的组织特点,机加工特点,给出了机加工参考参数,并讨论了改善等淬球铁机械加工性能的方法。     

等温淬火球铁斜楔的生产实践

通过降低碳当量，强化孕育，缩短球化处理后的浇注时间，可有效解决球铁斜楔在生产过程中产生的石墨开花问题，保证了ADI斜楔在铁路货车上的安全使用。     

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.     

等温淬火球铁(ADI)引锭杆的研制

介绍ADI引锭杆铸造生产工艺特点及其铸态组织要求,分析主要合金元素的作用,运用正交试验法对等温淬火球铁（ADI）引锭杆的热处理工艺进行了优化试验,并对该引锭杆的淬透性进行了检测。试验结果表明,最大壁厚为140mm的ADI引锭杆需要进行必要的合金化,合金元素的加入量为：0.2%～0.3%Mo、0.4%～0.5%Ni、0.5%～0.8%Cu;ADI引锭杆的优化热处理工艺为：在900℃奥氏体化保温90min,再进行360℃等温淬火,等温“时间窗口”为90～120min;在该成分与热处理工艺条件下,引锭杆可以淬透,能够获得以针状铁素体＋残余奥氏体为基体的组织,其力学性能达到QT900-8。     

超低碳等温淬火球墨铸铁变质剂的研究

根据相关文献对变质剂中组成元素进行分类,分析了有关元素在铁液中的作用及行为,设计出四种不同成分的变质剂,对超低碳等温淬火球墨铸铁(AD)I进行变质处理。试验结果表明,SC变质剂变质效果最好,能够在铸态得到圆整度好、数量少、分布均匀的细小石墨球,并且基体组织中不存在碳化物。对SC变质剂加入量进行优化,探索不同变质剂含量对超低碳ADI的石墨球数、石墨球大小以及基体组织的影响。但是,SC变质剂加入量的改变,对石墨球数和石墨球大小的影响并不明显。