典型轴瓦的组织和性能分析

Analysis on Microstructure and Properties of Typical Bearing Bushes

采用SEM,EPMA,EBSD等设备分析了某典型柴油内燃机主轴用进口轴瓦的显微组织及性能。结果表明:主轴上瓦由钢背、Al-Zn合金层、镍栅、Pb-Sn-Cu合金组成,主轴下瓦和连杆瓦由钢背、Cu-Pb-Sn合金层、镍栅、溅射AlSn20Cu层组成;采用纳米压痕仪测得主轴上、下瓦、连杆瓦镀层硬度分别为0.212,1.223,1.313 GPa;主轴上瓦合金层组织为颗粒状Pb,Si分布于等轴状Al晶粒中,主轴下瓦、连杆瓦合金层组织为树枝状Pb相分布于柱状Cu晶粒中;主轴上、下瓦和连杆瓦的钢背均为低碳钢,组织由铁素体和珠光体组成,但组织形貌不同,均存在D类氧化夹杂物。

The microstructure and properties of imported bearing bushes for a typical diesel spindle are analyzed by SEM,EPMA and EBSD.The results show that the upper bearing bush of spindle is composed of steel backing,Al-Zn alloy layer,nickel gate and Pb-Sn-Cu alloy,while the lower bearing bush of spindle and connecting rod bearing bush are composed of steel backing,Cu-Pb-Sn alloy layer,nickel gate and sputtered AlSn20Cu layer;the hardness of coating on upper,lower bearing bush of spindle and connecting rod bearing bush measured by nanoindentation instrument is 0.212,1.223 and 1.313 GPa respectively;the microstructure of alloy layer of upper bearing bush of spindle is granular Pb and Si distributed in equiaxed aluminum grains,while the microstructure of alloy layer of lower bearing bush of spindle and connecting rod bearing bush is dendritic Pb phase distributed in columnar copper grains;the steel backings of upper,lower bearing bush of spindle and connecting rod bearing bush are all made of low carbon steels,which are composed of ferrite and pearlite,but the microstructure is different,there are D-type oxide inclusions in steel backings.