Ti-6Al-4V基體上氮電弧熔化法制備TiN層的組織及性能

采用直流氮電弧熔化方法在鈦合金(Ti-6Al-4V)基體上原位制備了TiN表面層。采用掃描電子顯微鏡、X射線衍射和顯微硬度儀等分析測試手段對TiN表面層的組織、硬度及摩擦磨損性能等進行了分析。探討了電弧電流對TiN層組織及性能的影響。結果表明:通過氮電弧熔化法制備的TiN層組織為樹枝晶,氮化層中樹枝晶的含量隨著深度的增加而減少,表面層與基體為冶金結合;隨著電弧電流由60A增加到100A,所制備的TiN表面層中樹枝晶的含量增加,表面層的硬度及耐磨性能都提高;當電弧電流為100A時,所制備的TiN表面層的最高硬度可達到1885HV,約為基體硬度的5倍,抗磨損性能也顯著提高。     

2738模具钢表面激光熔覆Ni基WC复合涂层的摩擦磨损性能

在2738模具钢表面通过CO2激光熔覆制备Ni基WC复合涂层。分别对2738钢基体和Ni-WC激光熔覆层进行干摩擦试验。用三维表面形貌仪测量磨损体积,用扫描电镜观察磨痕的表面形貌。试验结果表明,Ni-WC复合涂层试样的硬度显著提高,表面硬度超过1200HV,保证了Ni-WC熔覆层的耐磨性。熔覆层的平均摩擦因数约为0.24,与2738钢基体的摩擦因数0.43相比,降低了约44%。熔覆试样的比磨损率比基体试样的比磨损率下降了96.7%,WC硬质相提高了摩擦副表面的承载能力。磨粒磨损为Ni-WC复合涂层的主要磨损机理。     

MPS中速磨煤机磨辊磨损机理研究

在半工业性运行试验条件下,对ＭＰＳ磨煤机磨辊的磨损机理进行了进一步模拟磨损试验。结果表明：尽管磨辊表面内外侧的磨损形貌特征存在较明显的差异,但其磨损机理却很相似,都为切削磨损、塑变疲劳磨损和脆性相断裂三种机制并存,且都以切削磨损为主,所不同的只是磨料对磨辊外侧区域的切削磨损作用远比对其内侧区域强烈,且切削方向也比内侧区域更加集中一致,这也正是磨辊在使用过程中内外侧磨损速率产生明显差异的根本原因。这种差异是由磨机本身的结构特点和运行特性所决定的。     

热轧高速钢轧辊失效分析

采用化学成分分析,金相检测和硬度检测等方法对高速钢工作辊失效进行分析,结果表明:化学成分不满足标准要求导致辊身硬度偏低,使材料容易产生裂纹,无法满足正常服役要求。     

Roll wear on finishing trains of ASP1700 hot strip mills

A great deal of research and practical production indicated that a perfect shape control system needs a precise prediction model of roll wear. According to the practical wear curve of work roll in Angang ASP1700 hot strip mill, which was measured by a roll-profilemeter, the model of wear curve caused by one single strip was estabfished. The prediction of work-roll wear was achieved by combining Fortran language and practical technology parameters. The calculated results agreed well with the measured.     

基于距离矢量路由协议的网络故障快速恢复方法

为了有效提高距离矢量路由协议处理网络故障的能力,提高网络的可用性,提出了一种基于 距离矢量路由协议的网络故障快速恢复机制,该机制包括基于预先计算生成的每目的多可行 下一跳的本地重路由策略和基于网络稳定性的触发更新策略. 分析和仿真结果显示,该机制可 以实现距离矢量路由网络的快速故障恢复,并能提高网络的稳定性和可用性.     

应用热缩绝缘材料提高110KV架空导线的绝缘水平

运用实例介绍了运用热缩绝缘材料提高 110KV架空导线绝缘水平的施工技术 ,并说明FS RD复合绝缘材料的主要技术参数及进行空气间隙击空试验的数据。     

高速瓦楞辊机构凸度参数综合的有限元法

通过模拟瓦楞辊机构的全工作状态、附加力的约束、几何约束、温度场的约束等建立有限元模型进行分析,从而获得了垂直于轴线任一截面上的位移 本文将这些位移与瓦楞辊端截面位移之差定义为各截面的凸度,各截面凸度连线便是凸度曲线     

高磷铸铁汽缸套磨损失效分析

文章分析研究了内燃机高磷铸铁汽缸套的磨损失效原因。对用磨粒磨损理论解释汽缸套最大磨损部位失效机理的观点提出了不同看法。研究认为,在汽缸套的最大磨损部位,其主要磨损机制在磨损过程中是有演变转化的,在正常磨损阶段主要表现出分层磨损特征,在严重磨损阶段以疲劳磨损为主,末期有粘着磨损产生。文章还提出,汽缸套磨损后沿轴线方向上不同区段的磨损特征是不同的。     

高速瓦楞辊啮合与纸板成型理论

建立了上瓦楞辊加压为移动和摆动的统一运动坐标系得出了统一形式的瓦楞辊啮合方程组应用计算机编程解出齿廓全部啮合点的通解并得到了瓦楞辊运动学性能图谱     

Failure analysis of wear of main clutch separating ring of heavy vehicles

The severe wear of separating ring is considered to be a main reason which leads to the improper declutch of the main clutch of heavy vehicles. The wear mechanism of the separating ring is not well understood. Scanning electron microscopy and transmission electron microscopy were employed to analyze the surface features and dislocation characteristics of the separating ring. The typical features of furrows and rolled tongue-like metal were found on the surface of separating ring by scanning electron microscopy observation, which can be considered as a major indi cation of the grain-abrasion. A zone of high density dislocation was noted on the subsurface of the separating ring by transmission electron microscopy observation, which implies the contribution of the severe impact on the surface of the separating ring in the wear process. The influences of the structure of the separating ring, the service condition and the in-service stress distribution on the wear behavior, were also analyzed. The results show that the failure of separating ring results from the impact wear and grain-abrasion together with the plastic deformation.     

Failure analysis of wear of main clutch separating ring of heavy vehicles

The severe wear of separating ring is considered to be a main reason which leads to the improper declutch of the main clutch of heavy vehicles. The wear mechanism of the separating ring is not well understood. Scanning electron microscopy and transmission electron microscopy were employed to analyze the surface features and dislocation characteristics of the separating ring. The typical features of furrows and rolled tongue-like metal were found on the surface of separating ring by scanning electron microscopy observation, which can be considered as a major indication of the grain-abrasion. A zone of high density dislocation was noted on the subsurface of the separating ring by transmission electron microscopy observation, which implies the contribution of the severe impact on the surface of the separating ring in the wear process. The influences of the structure of the separating ring, the service condition and the in-service stress distribution on the wear behavior, were also analyzed. The results show that the failure of separating ring results from the impact wear and grain-abrasion together with the plastic deformation. Foundation item: Project(41327040101) supported by the Pre-research Fund of General Armament Department; project(51489010104QT0101) supported by the Fund of State Key Laboratory of Re-manufacture Technology