B12G32A铝基轴承合金挡油环部件凝固成形工艺研究

Solidification Forming Process of Low Pressure Cast B12G32A Aluminum-Based Oil Deflector Parts

以B12G32A内挡油环与外挡油环为研究对象,设计了一种低压浇注凝固成形工艺,在平缓充型速度下实现了铸件自上而下与自外向内的顺序凝固。对其显微组织与力学性能进行分析测试,本体试样进行摩擦-磨损试验。结果显示:Al-Sn共晶体受界面张力作用,以网状包络形貌将初生α-Al基体焊合在一起,经140℃时效保温2.5 h后,本体试样平均抗拉强度、屈服强度与伸长率分别为134.0 MPa、115.3 MPa与15.3%。摩擦-磨损过程中低熔点Sn相不断被挤压成片状,粘着转移均匀覆盖在摩擦副表面,起到了良好的自润滑效果。

In the present study, B12G32A aluminum-based bearing alloy was used as an oil deflector material. A low pressure filling casting process was designed to realize the solidification sequence from the top to the bottom and from outside to inside of the B12G32A oil deflector castings, and the microstructure was observed and mechanical properties were measured for the samples from casting itself. The results reveals that the primary α-Al matrix with network morphology of is surrounded by Al-Sn eutectic phases due to the interfacial tension, after aging for 2.5 h at 140℃, the average tensile strength, yield strength and elongation are 134.0 MPa, 115.3 MPa and 15.3% respectively. During the friction-wear process, the low-melting Sn phase is continuously extruded into sheet shape, and transfers to the surface of the friction pair with uniform distribution, leading to a good self-lubricating effect.