铁基粉末冶金刹车材料加压烧结冷却水流量研究

The Research of Cooling Water Flow for Pressure Sintering of Iron-based Powder Metallurgy Brake Materials

对于铁基粉末冶金刹车材料而言,加压烧结冷却过程中冷却水流量是保证材料获得优良综合性能的关键参数之一。通过粉末冶金方法制备了铁基刹车材料,研究了空冷和不同水流量(12 L/s、27 L/s、40 L/s)条件下,材料组织、力学性能及摩擦磨损性能的变化规律。通过光学显微镜和扫描电镜分析了材料性能变化规律的形成原因。结果表明:冷却水流量与冷却时间及冷却速度并不是简单的正比例关系,当冷却水流量为27 L/s时,冷却所用时间最短,材料冷却速度最大,材料组织以片状珠光体和粒状珠光体为主,其它条件下材料的组织主要为片状珠光体,但材料力学性能随冷却水流量变化不显著,同时,当冷却速度为27 L/s和40 L/s时,材料具有最大的密度;摩擦因数比较稳定,材料表面形成了完整的氧化膜,磨损量最小。

During pressure sintering of iron-based powder metallurgy brake materials, the cooling water flow was one of the most important parameters. Iron-based brake materials were made by powder metallurgy method, the effect of the cooling water flow on the microstructure, mechanical properties and friction properties of iron-based friction materials was studied. The resultant mechanisms were discussed by observation and analysis of the properties of iron-based friction materials with different cooling water flow. The results show that there is not simple direct proportion relation between cooling water flow, cooling time and cooling rate. When the cooling water flow is 27 L/s, cooling time is minimum, the cooling rate of materials is maximum, lamellar pearlite and divorced pearlite are major contexture, under other conditions, the contexture of materials is lamellar pearlite, but the mechanical properties change insignificant. When the cooling water flow is 27 L/s, the density of materials is maximum, the change of friction coefficient is stable, the complete oxidation films come into being on the surface of materials, the wear of materials is minimum.