含铬蠕墨铸铁摩擦磨损性能研究

用自制的干摩擦磨损试验机．研究了含铬蠕墨铸铁在不同接触压力及不同摩擦速度时的干摩擦磨损性能。结果表明：随着接触压力和摩擦速度的提高，含铬蠕墨铸铁的磨损量呈线性增加，摩擦系数先降低而后趋向于相对稳定；随着含铬量增加，蠕墨铸铁的磨损量降低，摩擦系数在碳化物含量为5％～6％左右时出现极大值；在试验条件下，含铬蠕墨铸铁的摩擦磨损性能优于普通蠕墨铸铁。     

变温条件下石墨形态对缸套铸铁磨损性能的影响

为了研究缸套铸铁材料石墨形态对其磨损过程的影响,选取了灰铸铁、蠕墨铸铁和球墨铸铁3种具有不同石墨形态的铸铁材料为研究对象,分别在不同温度下对其进行了干摩擦磨损实验。结果表明:灰铸铁的摩擦系数及磨损量随温度的上升而上升,而蠕墨铸铁及球墨铸铁随温度的上升呈现先上升后下降的变化趋势;常温下灰铸铁的摩擦系数及磨损量最大,耐磨性能最差;高温时灰铸铁的摩擦系数及磨损量仍然最大,蠕墨铸铁的摩擦系数大于球墨铸铁,但磨损量最小,耐磨性能最优。     

铸铁的干滑动摩擦磨损

系统地研究了铸铁材料进行了干滑摩擦条件下的摩擦学特性。讨论了钢铁摩擦副的摩擦学规律;铸铁的石墨形态、合金元素及其体组织对于滑动摩擦学特性的影响。研究结果表明：墨铸铁是制作制动部件的合适选材。     

Mn和CE对蠕墨铸铁组织及其摩擦磨损性能的影响

采用自制的摩擦磨损实验机，对不同碳当量及不同Mn含量的蠕墨铸铁的摩擦磨损性能进行了研究。结果表明：含Mn量0．9％～1．5％、基体以珠光体为主的蠕墨铸铁具有较高的摩擦系数和较小的磨损率，碳当量以不高于4．2％为宜。     

碳化铬/Ni3Al复合堆焊层组织及摩擦磨损分析

采用光学显微镜、扫描电镜、电子探针及X射线衍射分析钨极氩弧堆焊碳化铬增强Ni3Al基复合堆焊层的组织结构,并采用销盘式干摩擦磨损试验机对堆焊层与活塞环用蠕墨铸铁材料的干摩擦磨损性能进行试验比较.结果表明,复合堆焊层内形成Ni3Al金属间化合物基体,其中弥散分布有大量细小的块状和条状碳化物硬质相Cr3C2和Cr7C3;焊接时焊丝中Cr3C2颗粒溶解析出,重新析出的碳化铬颗粒中包含Fe和Ni元素,碳化铬颗粒与Ni3Al基体形成良好的冶金结合;弥散分布的碳化铬颗粒和Ni3Al基体固溶强化的Cr元素决定了堆焊层具有较高的硬度.室温条件下,复合堆焊层具有优异的耐干摩擦磨损性能,其摩擦系数为0.23,远低于活塞环蠕墨铸铁的0.39;磨损率仅为蠕墨铸铁材料的43%.     

蠕墨铸铁在铁道车辆制动系统中的应用研究

在分析车辆制动器摩擦温度场的基础上 ,研究蠕墨铸铁在铁道车辆制动系统中的使用性能 ;研究结果表明 ,在车辆制动器服役条件下 ,摩擦速度与接触压力的提高 ,摩擦副的摩擦系数显著降低 ,磨损率显著增加 ;在所研究的不同石墨形态的铸铁中 ,蠕墨铸铁不但具有低而稳定的磨损率 ,而且具有高而稳定的制动性能 ,是制造车辆制动器部件的合理选材。     

不同石墨形态的铸铁干滑动摩擦学性能研究

在MMs-1G型高速摩擦磨损试验机上对不同石墨形态的铸铁进行高速干滑动摩擦磨损试验.利用SEM观察并分析摩擦面磨损形貌及磨损机理.结果表明:石墨形态对铸铁的摩擦磨损性能有显著影响;随着速度的增加,摩擦系数降低,磨损率增大.     

钒钛蠕墨铸铁的力学性能分析

以钒钛生铁为原材料经蠕化处理后得到钒钛蠕墨铸铁.测试了钒钛蠕墨铸铁的力学性能,评估了其石墨形态和基体组织,通过扫描电镜观察并分析了显微组织和断口形貌.结果表明:钒钛蠕墨铸铁金相组织中蠕化率和基体中的珠光体含量均较高,具有优良的常温力学性能,钒钛元素在蠕墨铸铁中以钒钛碳化物及固溶干渗碳体的形式存在,钒钛等合金元素对蠕墨铸铁力学性能的影响有有利的一面,也有不利的一面,钒钛蠕墨铸铁拉伸试样最终呈韧-脆混合断裂.     

喷砂表面处理控制滑动摩擦尖叫噪声

采用球—平面接触方式,对喷砂处理的制动盘蠕墨铸铁试样进行了滑动摩擦噪声试验,并与光滑表面样品试验对比。在对摩擦噪声特性和摩擦磨损特性进行综合分析的基础上,探讨控制滑动摩擦尖叫噪声触发和演变规律的关键界面因素,研究了喷砂表面对滑动摩擦尖叫噪声的影响及其机理。结果表明:喷砂处理表面能明显的抑制界面摩擦尖叫噪声的产生,且表面粗糙度越大,抑制尖叫噪声效果越明显,界面微凸体的分布和磨损情况对摩擦尖叫噪声的产生及演变具有关键的影响。该试验条件下摩擦尖叫噪声的产生主要归因于磨屑堆积、粘着剥落和犁沟等界面因素引起界面摩擦力剧烈波动,诱发了摩擦系统的自激振动。相比光滑表面,喷砂处理表面的微凸体接触磨损"平台"表面的磨屑堆积、粘着剥落和犁沟等现象较轻,引起摩擦力波动的能量较弱,产生的尖叫噪声强度较低。     

炼制动闸瓦新型材料的探讨——磷、硼蠕墨铸铁的组织及性能试验

本文研究了磷、硼对蠕墨铸铁组织、性能,摩擦磨损和工艺性能的影响规律。研究表明:随着磷、硼含量的增加,蠕墨铸铁的硬度提高,抗拉强度降低,摩擦系数提高,磨耗量降低,适合于作为制动闸瓦的材质。     

Tribological characteristics of compacted graphite cast iron in dry sliding condition

In tribological system, friction pairs are the core.Different friction pairs show different tribologicalcharacteristics. Dry sliding friction means that there is noliquid lubricator in the process of wear and friction. Inmost cases, friction surfaces contact each other directly,while under some operating conditions, there exists solidlubricant. Among many friction pairs studied, the drysliding friction pairs with background of practicalapplication for brake system increasingly attract theatten…     

Sliding wear behavior of high velocity arc sprayed Fe-Al coating

The friction and wear behavior of Fe-Al intermetallics based coating produced by high velocity are spraying technique under dry sliding at room temperature were investigated using a ball-on-disc tribotester. The effect of sliding speed on friction coefficient and wear of the coating was studied. The worn surface of the coating was analyzed by scanning electron microscope (SEM) to explore sliding friction and wear mechanism. The results show that the variations of friction coefficient can be divided into three distinct steps during the trail. Both the friction coefficient and the wear of the coating increase with increased sliding speed due to accelerated crack propagation rate and lamellar structure with poor ductility of the coating. The coating surface is subjected to alternately tensile stress and compression stress during sliding wear process, and the predominant wear mechanism of the coatings appears to be brittle fracture and delamination.     

速度和压力对SiCp增强铝基复合材料摩擦磨损性能的影响

研究了颗粒增强铝基复合材料及其基体的摩擦磨损性能。基体和复合材料的耐磨性有明显差异，复合材料的主要磨损形式是磨粒磨损，基体材料的主要磨损形式是粘着磨损。复合材料具有低的磨损率和稳定的摩擦因数，因此具有良好的耐磨性。     

三维网络陶瓷增强铝基复合材料的干摩擦磨损性能

设计和制备了一种新型的三维网络陶瓷(骨架)增强铝合金复合材料.研究了铝合金及不同成分复合材料在不同温度及载荷下的摩擦系数和磨损率;用扫描电镜(SEM)观察其磨损表面,并分析了三维网络陶瓷(骨架)对铝合金磨损机制的影响.结果表明:复合材料的耐磨性远优于铝合金,而且随着三维网络陶瓷体积分数、温度及载荷的增加,复合材料的抗磨损性能明显提高;这种新型复合材料的摩擦系数随载荷变化保持稳定;在很宽的温度范围内,摩擦系数的稳定性均优于铝合金.这是由于三维网络陶瓷在磨损表面形成硬的微凸体起承载作用,其独特的结构制约了基体合金的塑性变形和高温软化,有利于磨损表面氧化膜的留存.     

Friction and wear characteristics of polymer-matrix friction materials reinforced by brass fibers

This study is an investigation of friction materials reinforced by brass fibers, and the influence of the organic adhesion agent, cast-iron debris, brass fiber, and graphite powder on the friction-wear characteristics. Friction and wear testing was performed on a block-on-ring tribometer (MM200). The friction pair consisted of the friction materials and gray cast iron (HT200). The worn surface layers formed by sliding dry friction were examined using scanning electron microscopy (SEM), x-ray energy-dispersive analysis (EDX), and differential thermal analysis-thermogravimetric analysis (DTA-TAG). The experimental results showed that the friction coefficient and the wear loss of the friction materials increased with the increase of cast-iron debris, but decreased with the increase of graphite powder content. The friction coefficient and wear loss also increased slightly when the mass fraction of brass fibers was over 19%. When the mass fraction of organic adhesion agent was about 10–11%, the friction materials had excellent friction-wear performance. Surface heating from friction pyrolyzes the organic ingredient in the worn surface layer of the friction materials, with the pyrolysis depth being about 0.5 mm. The surface layers were rich in iron but poor in copper, and they were formed on the worn surface of the friction material. When the mass fraction of brass fibers was about 16–20%, the friction materials possessed better wear resistance and a copper transfer film formed on the friction surface of counterpart. Fatigue cracks were also found in the worn surface of the gray cast-iron counterpart, with fatigue wear being the prevailing wear mechanism.     

原位合成Al2O3增强铝基复合材料的摩擦磨损性能

通过采用粉末冶金和原位合成技术相结合的近净成形技术制备Al-5％Si-Al2O3复合材料,并运用M一2000摩擦磨损试验机对该复合材料的摩擦磨损性能进行研究。通过单一变量比较法分析载荷和滑动速度对Al-5％Si-Al2O3复合材料摩擦磨损性能的影响,同时对长时间连续磨损下该材料的摩擦性能进行研究。通过扫描电子显微镜对Al-5％Si-Al2O3复合材料的磨损表面进行观察,并分析其磨损机制。结果表明,随着载荷的增大,试样的磨损量和摩擦因数均增加;随着滑动速度的增大,试样表面的升温使得产生氧化层的速率增加,试样的磨损量和摩擦因数均减少。在长时间的连续磨损过程中,由于初始时发生粘着磨损,试样的摩擦因数随着滑动距离的增大而增大。然后,试样表面氧化层的形成和破坏趋于动态平衡,试样表面相对稳定,其摩擦因数也随之趋于平稳。铝基复合材料的磨损机制主要为磨粒磨损、粘着磨损和氧化磨损。     

Influence of composition on friction-wear behavior of composite materi-als reinforced by brass fibers

In the study, for the composite materials reinforced by brass fibers, the influence of dominant ingredients, such as organic adhesion agent, cast iron debris, brass fiber, and graphite powder, on the friction-wear characteristics was investi-gated. The friction-wear experiment was carried out on the block-on-ring tribometer MM200. The worn surfaces of the fric-tion pair consisting of the composite materials and grey cast iron HT200 under dry sliding friction were examined using scanning electron microscope (SEM), energy dispersive analysis (EDX) and differential thermal analysis-thermogravimetric analysis (DTA-TAG). The experimental results showed that the friction coefficient and the wear loss of the composite ma-terial increase obviously with the increase of cast iron debris content, but decrease obviously with the increase of graphite powder content, and increase a little when the mass fraction of brass fiber was over 19%, and the orientation of brass fiber has obvious influence on friction-wear prop     

高速球铣路径对淬硬钢SKD11表面摩擦特性的影响

通过高速铣削试验与环-块摩擦磨损试验,借助白光干涉仪、超景深三维显微镜、显微硬度计等分析检测设备,研究了走刀路径对淬硬模具钢SKD11表面摩擦特性的影响。结果表明:球铣加工表面摩擦特性具有方向性,当走刀方向与摩擦方向垂直时,摩擦因数最小,磨痕宽度最窄,当二者夹角成45°时,摩擦因数最大,磨痕宽度最宽。球铣走刀路径影响加工表面形貌取向,表面形貌通过改变接触应力和磨屑捕捉能力来影响犁耕效应和黏着效应,进而影响摩擦特性。干摩擦工况下,主要磨损机理是磨粒磨损与氧化磨损,试验15 min后表面微沟槽形貌均已消失;而润滑工况下,表面微沟槽依然清晰,走刀路径与摩擦方向夹角成0°与45°试样表面出现磨粒磨损特征,而夹角成90°试样表面无明显划痕,表明采用该路径进行球铣加工具有较好的减磨效果。