柴油发动机湿式气缸套磨损穴蚀的原因及预防

分析了柴油发动机湿式气缸套磨损及穴蚀的特点和原因，提出了相应的预防措施。     

Experimental Study on the Milling of a Ti Beta 21S

Ti Beta 21S (Ti-15Mo-2.7Nb-3Al-0.2Si) was devel op ed by TIMET in 1989. It is a metastable beta titanium alloy that offers subs tantial weight reductions over other engineering materials. Compared with common beta Ti alloys, it offers the high specific strength, good cold formability, im proved oxidation resistance, elevated temperature strength, creep resistance, an d thermal stability. Besides the common characters of titanium alloy, such as po or heat diffusivity, low elastic modulus, Ti Beta 21S has ...     

Effect of Electrospark Alloying Process on Microstructure and Properties of the coating

Using electrospark alloying machine, a series of experiments were carried out to investigate the effect of electrospark surface strengthening process on the microstructure and the properties of the coatings with ultrafine cemented carbide as electrode material and white cast iron as substrate material. The results indicated that the optimum process parameters to be used reached a satisfying coating surface. Wear test results showed the coatings had a high wear-resistance.     

High Speed Cutting Inconel 718 with Coated Carbide and Ceramic Inserts

High speed machining (HSM) technology is one of important aspects of advanced manufacturing technology. Nickel-based superalloys have been widely used in the aircraft and nuclear industry due to their exceptional thermal resistance and the ability to retain mechanical properties at elevated temperatures of service environment over 700 ℃. However, they are classified as difficult-to-cut materials due to their high shear strength, work hardening tendency, highly abrasive carbide particles in the microstructur...     

难熔金属碳化物覆层磨损率的统计分布

采用销／盘磨损试验,测定碳化钒（ＶＣ）和碳化铌（ＮｂＣ）覆层的大量磨损数据．借助统计方法,得出碳化物覆层磨损系数Ｋ服从对数正态分布．估计了不同配副试样Ｋ的分布参数和位置统计量,作出了直方图和密度函数曲线,评价了销／盘磨损特性．结果表明：中位数比算术平均值能更好地描述实际平均磨损;随着载荷的增加,位置统计量趋于接近;碳化物覆层磨损抗力是淬火钢的６～１１倍．     

A View on Wear Mechanism of Metallic Card Clothing

The wear mechanism of metallic card clothing, used in textile industry, was analyzed. A fast wear test for metallic card clothing racks was developed, which was used as collecting the wear metal particles. The failure type of card clothing was analyzed by the mean of scanning electron microscopy （SEM） and ferro-spectrum technology. The results show that the main wear mechanism of metallic card clothing is low load and high repetition interval fatigue wear caused by friction force between fiber and metal wire teeth. The appropriate quenching microstructure, which improves the wear resistance of the metallic card clothing rack is also discussed.     

超音速火焰喷涂WC-12Co涂层的磨粒磨损行为研究

对超音速火焰WC-12Co涂层进行了磨粒磨损试验,研究了磨粒磨损试验参数对涂层性能的影响,并通过SEM对涂层表面的显微形貌进行了观察分析,探讨了WC-12Co涂层的磨粒磨损失效机制.结果表明:涂层的失重随试验载荷及磨料直径的增加而增加;在载荷或磨料粒度较大时.涂层的磨损失效形式为晶粒剥落及犁沟切削相结合;当载荷或磨料粒度较小时,其失效形式主要为晶粒剥落方式.     

原位合成TiC-TiB_2复合涂层的组织结构及耐磨性

以Ti粉、B4C粉和Fe粉为原料,利用氩弧熔敷技术在Q235钢基体表面制备出以TiC和TiB2颗粒为增强相的原位自生金属基复合涂层.利用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计和滑动磨损试验机对复合涂层的显微组织、硬度和耐磨性进行了研究.实验结果表明:涂层与基体呈冶金结合,无裂纹、气孔等缺陷;氩弧熔敷层组织是由弥散分布的TiC、TiB2颗粒和α-Fe基体组成,TiC呈八面体或花瓣枝晶状,TiB2呈六边形或棒状.涂层中随着B4c质量分数的增加,TiB2由短棒状或六边形变为棒状,TiC的质量分数也随之增加.具有较多棒状TiB2的涂层,其硬度最高、摩擦系数最小,耐磨损性能最好.     

二烷基二硫代磷酸镧润滑添加剂的构效关系

为研究新型油溶性稀土润滑添加剂二烷基二硫代磷酸镧(LaDDPs)的结构与性能关系,合成了10种含不同碳原子数的伯、仲炕基LaDDPs.利用四球试验机考察了其在500SN基础油中的摩擦磨损性能和极压性能,并探讨了烷基碳链的长短和伯、仲烷基结构对LaDDPs性能的影响.结果表明,含3～8个碳原子烷基的LaDDPs均具有较好的抗磨减摩性能和极压性能.随着碳原子数的增加,LaDDPs的抗磨减摩性能明显提高,其中仲烷基LaDDPs性能优于伯烷基LaDDPs;LaDDPs的极压性能随碳原子数的增加而降低,碳链的连接方式对LaDDPs的极压性能无明显影响.     

铝锡轴承合金的摩擦磨损机理与性能

铝锡轴承合金对大型载重汽车、坦克、高速汽车、拖拉机等的高速高压柴油机的发展有重要的意义。提高铝锡合金的耐摩擦磨损性能可节省大量能源并延长零件的使用寿命,如何取得具有优良的耐摩擦磨损的铝锡合金成为研究的重点。本文介绍了提高铝锡合金的耐摩擦磨损性能的措施及其影响因素,总结铝锡合金中锡元素含量改变、合金元素的添加、热处理与制备工艺的改变对铝锡合金的显微组织以及耐摩擦磨损性能的影响。