从美国ADI铸件获奖看ADI的发展

介绍了几年来获美国铸造学会最高奖的ADI铸件.从获奖ADI铸件看出ADI从初期取代单件的铸钢件、锻钢件,到逐渐取代复杂的铸钢件、锻钢件、焊接件等装配而成的组装件.ADI的高强度、高韧性、高疲劳强度及优越的耐磨性为设计工程师提供了更具潜力的铸件材料.     

等温淬火球墨铸铁及水平连铸型材ADI的发展

等温淬火球墨铸铁(简称ADI)具有高强、高韧、耐磨性和减振降噪性能好等诸多优点。水平连铸球铁型材的组织致密、晶粒细小、石墨球化率高、球化级别高,无缩松、缩孔、夹渣等缺陷,是生产ADI的理想铸件。本文对ADI的特点、国内外的研究和应用状况进行了分析,认为采用水平连铸球铁型材替代普通铸件作为生产ADI的坯件,是提高我国ADI的产品质量、推动ADI在机械行业应用的有效途径。     

等温淬火球铁(ADI)铸件获美国铸造学会最高奖

ADI在美国持续不断发展.2003年美国铸造学会每年一次的铸件竞赛15件获奖铸件中,5件ADI铸件获得最高奖.文中叙述两件获奖ADI铸件:建筑和园林用的装载机ADI驱动轮铸件和福特野马眼睛蛇(Ford Mustang Cobra)跑车底盘悬架控制臂.铸件结构紧凑,原材料投料量减少,少用或不用机加工、焊接和装配,设计灵活,重量减轻,尺寸精度提高,成本降低等.     

轻量化创新是ADI发展的方向

制造业技术创新是国家经济增长的支撑,是企业获得竞争优势的决定因素。在制造业创新中,轻量化创新是重要的内容。ADI作为一种高强度轻量化材料,轻量化创新是发展方向。发达国家都很重视轻量化ADI铸件的开发。实际上采用ADI直接代替铸钢,锻钢件就已经减重10%。然而,利用ADI优越的力学性能,利用铸造较之焊接、锻造和装配在成型方面的优势,利用铸件设计、凝固模拟、应力模拟可以设计和制造出质量更轻、刚度更好、强度更高、功能更强、结构更美、附加值更高的轻量化ADI铸件。论述了发达国家以及中国在ADI轻量化创新方面的典型实例和经验,并对中国ADI轻量化创新如何深入发展提出了一些建议。     

等温淬火球墨铸铁滑动摩擦磨损性能的研究

研究了ADI在有润滑的磨擦条件下的耐磨性并分析了其磨损机理。结果表明,ADI在有润滑的滑动摩擦中的耐磨性随奥氏体化温度(850～950℃)的升高和等温湿度(300～400℃)的升高而下降,其磨损机制主要是粘着磨损。最后提出了在摩擦磨损条件下如何选用ADI的参考建议。     

ZJ001型真空吸铸机

ZJ001型真空吸铸机由一机部铸缎机械研究所投计由青岛生建机械厂试制,于1965年12月完成并经鉴定合格。真空吸铸是一项先进的铸造技术,具有铸件质量好、生产效率高、劳动条件好等优点。用其空吸蕴法镌出的工件与一般砂型铸造比较有下述之优点: 1.蟋件无缩松、斜孔、气孔、砂眼等铸造缺陷。金相组织细密,晶粒细小; 2.铸件机械性能显著提高; 3.生产效率高,每小时可达40件左右; 4.铸件表面光洁,减少加工刀具磨损; 5.改善劳动条件。     

影响缸体用灰铸铁加工性能的因素

近年来，随着中外技术合作的加强，在许多中外合资厂中都出现了缸体灰铸铁件的力学性能、金相组织与国外的铸件相当，都符合要求，但加工时刀具磨损要比进口灰铸件严重的多的现象。这严重影响了缸体铸件的国产化。如某一铸造二厂在对自己生产的捷达车发动机缸体铸件进行加工时发现，在相同的刀具和加工工艺的条件下，其刀具磨损是国外同类铸件刀具磨损的10倍。铸件的加工性能可从切削力、刀具磨损和表面光洁度等方面考虑。影响灰铸件的加工性能的因素是多方面，石墨的形态和含量、合金元素、微量元素和铸造工艺等都对灰铸铁件加工性能有很大影响。     

球墨铸铁奥氏体回火后在重型机械上的应用

对球墨铸铁进行奥氏体回火,经过约十年的试验研究工作,已初获成功。现在已经有一百多个机械制造厂用于制造重型机械、运输机械、汽车、拖拉机等设备的重型关键零件。经过奥氏体回火的球墨铸铁(简称为ADI),其强度、耐磨、韧性、耐疲劳等性能可以和铸钢、锻钢相比美。ADI零件的壁厚可以比锻钢、铸钢件薄、重量轻,这一点对汽车及运输设备来说是很重要的。ADI铸件所需要的生产工具比锻钢少,费用也低。零件形状可以比较复杂,如中空件。其机械加工性能也良好。     

中碳低合金耐磨钢及其磨料磨损行为的研究

开发了一种中碳低合金耐磨钢.在同样的磨损条件下(湿砂磨料磨损、冲击磨料磨损及腐蚀磨损),本钢种的抗磨性和抗腐蚀磨损性能均优于普通低合金钢、中锰钢及高锰钢.它可以代替高锰钢用于制造易磨损件,尤其适用于制造湿式球磨机衬板类铸件.     

ADI链轮的生产

总结了ADI铸件质量和热处理工艺的控制措施,介绍了ADI链轮的生产条件和工艺方法.采用CAD/CAM制作高强度铸件金属模型,碱性酚醛树脂砂造型,稳定生产出性能要求R<,m>≥1 400 MPa、A≥2%、硬度45±2 HRC,基体组织完全淬透为残余奥氏体+贝氏体的ADI链轮.解剖后的铸件内部致密,无气子孔、夹渣、缩松等铸造缺陷;铸件的尺寸精度、表面粗糙度符合图纸要求.     

ADI的疲劳强度

论述了ADI的疲劳强度。ADI的疲劳强度优于普通球铁,具有与锻钢相当或比锻钢更好的疲劳强度。表面滚压或喷丸可以进一步增加ADI的疲劳抗力而与气体氮化钢和表面碳化处理钢相匹敌,使ADI完全可以在一定应用中替代碳钢和低合金钢铸件,锻钢件。     

Wear resistance properties of austempered ductile iron

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.     

铬和钼对精铸热锻模具钢高温磨损行为的影响

采用销盘式高温磨损试验机,研究不同Cr、Mo含量的精铸热锻模具钢的高温磨损行为;通过TEM、SEM和XRD分析,研究钢的显微组织和磨损表面的形貌和结构;探讨了成分、组织、性能与高温磨损的关系及高温磨损机理。结果表明,随着Cr、Mo分别从3%和2%增加到5%和4%,热稳定性和硬度分别得到明显降低或略提高,当含4.0%Cr和3.0%Mo时,耐磨性最好。高温磨损抗力对钢的热稳定性和热强性变化不敏感,而对钢的组织或韧性变化极敏感。过高的铬（5%）虽降低热稳定性和热强性,但仍具有较高的高温耐磨性;而过高的钼（4%）虽然热稳定性和热强性提高,由于Mo6C沿晶界或板条界析出,韧性降低,则高温耐磨性明显降低。精铸热锻模具钢高温磨损机理为氧化磨损和氧化物的疲劳剥落,磨面上产生的氧化物主要为Fe3O4和Fe2O3,其对磨损起到保护作用,氧化物的疲劳剥落导致磨损。     

Influence of carbon content on wear resistance and wear mechanism of Mn13Cr2 and Mn18Cr2 cast steels

By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to study the influence of different carbon contents(1.25 wt.%, 1.35 wt.%, and 1.45 wt.%) on the wear resistance and wear mechanism of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The research results show that the wear resistance of the Mn18Cr2 cast steel is superior to that of the Mn13Cr2 cast steel under the condition of the same carbon content and different impact abrasive wear conditions because the Mn18Cr2 cast steel possesses higher worn work hardening capacity as well as a more desirable combination of high hardness and impact toughness than that of the Mn13Cr2 cast steel. When a 4.5 J impact abrasive load is applied, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the former dominates. When the carbon content is increased, the worn work hardening effect becomes increasingly dramatic, while the wear resistance of both steels decreases, which implies that an increase in impact toughness is beneficial to improving the wear resistance under severe impact abrasive wear conditions. Under the condition of a 1.0 J impact abrasive load, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the latter plays a leading role. The worn work hardening effect and wear resistance intensify when the carbon content is increased, which implies that a higher hardness can be conducive to better wear resistance under low impact abrasive condition.     

奥氏体—贝氏体合金球铁磨球的研制与应用

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。     

Feasibility of electro-slag cast steel for hot-working tools

A study on electro-slag cast steel has been performed to assess the feasibility of its use in hot-working tools in place of traditional forged steels. In this study, some important material properties that are essential for the proper performance of hot-working tool steels have been measured. The properties of the electro-slag cast steel are compared with those of hot-working tool steels currently used in industrial practices. The use of electro-slag cast steel in specific applications has been evaluated and compared with the operational performance of currently used steels in industrial environments. The wear resistance, impact toughness, thermal fatigue resistance, and repair weldability of electro-slag cast steel have been determined. The material properties were found to be comparable to existing hot-working tool steels. The number of effective blows obtained from an industrial application test also confirms that electro-slag cast steel is a feasible material for hot-working tools.     

Effect of the carbide phase on the tribological properties of high-manganese antiferromagnetic austenitic steels alloyed with vanadium and molybdenum

Effect of special carbides (VC, M ₆C, Mo₂C) on the wear resistance and friction coefficient of austenitic stable (M _s below −196°C) antiferromagnetic (T _N = 40–60°C) steels 80G20F2, 80G20M2, and 80G20F2M2 has been studied. The structure and the effective strength (microhardness H _surf, shear resistance τ) of the surface layer of these steels have been studied using optical and electron microscopy. It has been shown that the presence of coarse particles of primary special carbides in the steels 80G20F2, 80G20M2, and 80G20F2M2 quenched from 1150°C decreases the effective strength and the resistance to adhesive and abrasive wear of these materials. This is caused by the negative effect of carbide particles on the toughness of steels and by a decrease in the carbon content in austenite due to a partial binding of carbon into the above-mentioned carbides. The aging of quenched steels under conditions providing the maximum hardness (650°C for 10 h) exerts a substantial positive effect on the parameters of the effective strength (H _surf, τ) of the surface layer and, correspondingly, on the resistance of steels to various types of wear (abrasive, adhesive, and caused by the boundary friction). The maximum positive effect of aging on the wear resistance is observed upon adhesive wear of the steels under consideration. Upon friction with enhanced sliding velocities (to 4 m/s) under conditions of intense (to 500–600°C) friction-induced heating, the 80G20F2, 80G20M2, and, especially, 80G20F2M2 steels subjected to quenching and aging substantially exceed the 110G13 (Hadfield) steel in their tribological properties. This is due to the presence in these steels of a favorable combination of high effective strength and friction heat resistance of the surface layer, which result from the presence of a large amount of special carbides in these steels and from a high degree of alloying of the matrix of these steels by vanadium and molybdenum. In the process of friction, there are formed nanocrystalline austenitic structures possessing high effective strength and wear resistance on the wear surface of these steels.     

石墨及碳化物对高镍铬无限冷硬铸铁轧辊耐磨性的影响

本文研究了具有不同石墨和碳化物含量的高镍铬无限冷硬铸铁轧辊材料在滚动摩擦和干滑动摩擦条件下的摩擦学特性，考察了高镍铬无限冷硬铸铁中石墨和碳化物数量、分布对其摩擦学特性的影响。研究结果表明，组织中的石墨和碳化物数量、形态和分布对材料的耐磨性有较大影响。石墨含量在低于9．21％时，增加石墨量并适当减少碳化物量可以提高材料的耐磨性；呈均匀分布的长片状石墨和连续网状分布的碳化物对提高高镍铬无限冷硬铸铁轧辊的耐磨性有显著意义。     

锻焊和形变热处理对铸造高锰钢辙叉耐磨性的影响

铸造高锰钢是应用非常广泛的耐磨材料之一,但是由于铸造高锰钢存在缩松、气孔、晶粒粗大等铸造缺陷,导致其存在力学性能降低、服役稳定性差等难题。为了减少铸造高锰钢辙叉孔洞类缺陷和细化奥氏体晶粒,研究了锻焊和形变热处理(FW&TMCP)对铸造高锰钢辙叉耐磨性的影响,首先对铸造高锰钢和FW&TMCP高锰钢进行常规拉伸性能测试,然后在不同载荷作用下对铸造高锰钢和FW&TMCP高锰钢进行摩擦磨损试验。结果表明,FW&TMCP高锰钢的强塑性远高于铸造高锰钢,应变硬化速率也高于铸造高锰钢。微观组织结果显示FW&TMCP高锰钢的孔洞类缺陷减少了82%,致密度大幅提高。随着摩损载荷的增大,两种状态高锰钢摩擦因数均逐渐减小。在施加相同磨损载荷时,铸造高锰钢的摩擦因数小于FW&TMCP高锰钢;FW&TMCP高锰钢的塑性变形程度更小,耐磨性更高。随着磨损载荷的增大,两种状态高锰钢的磨损机制均由粘着磨损转变为磨粒磨损。