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采用粉末冶金工艺制备含4种粒度(20μm、30μm、50μm、70μm)铁粉增强的铜基摩擦材料,研究铁粉粒度对材料力学性能和制动摩擦性能的影响。采用TM-1型惯性试验台测试材料的制动摩擦性能,试验初速度为50~380 km/h。结果表明:铁粉粒度从20μm增加到70μm时,材料硬度从55.67 HRB降低到31.83HRB,剪切强度从12.56 MPa下降到10.27 MPa。这种硬度和强度的下降使大粒度样品表现出反常的摩擦特性:随着制动速度的提高,铁粉粒度为70μm的F70样品的摩擦因数不降低反而升高,当制动速度从120 km/h上升到380 km/h时,摩擦因数从0.338持续升高到0.356,并且从350 km/h后摩擦因数稳定不变。这种高而稳定的摩擦因数是保证列车在高速下紧急制动、平稳停驶所必需的。
The effects of iron particle size on mechanical properties and brake friction properties were studied by powder metallurgy process. The effects of iron particle size on the mechanical properties and brake friction properties were studied. The TM-1 type inertial test rig was used to test the brake friction performance of the material. The initial test speed was 50-380 km / h. The results show that the hardness decreases from 55.67 HRB to 31.83 HRB and the shear strength decreases from 12.56 MPa to 10.27 MPa when the particle size increases from 20 μm to 70 μm. The decrease of the hardness and strength of the large-size samples showed abnormal frictional characteristics. With the increase of the braking speed, the friction coefficient of the F70 sample with the iron powder size of 70μm increased without any decrease. When the braking speed increased from 120 km / h increased to 380 km / h, the friction coefficient increased continuously from 0.338 to 0.356, and the friction coefficient remained stable after 350 km / h. This high and stable friction factor is necessary to ensure that the train is braked urgently and smoothly at high speed.