Research on the Performance Influence of Partly Granulation Technology for Friction Materials

Abstract

This paper experimentally investigated the friction, wear performance, density, hardness and impact performance of pelletizing friction material. The research was used partly granulation process for prepare friction material. Experiments showed that: When the proportion of partly granulation friction material and powder was mixed with 2:1, the friction coefficient was better, which compared to 1:1 and 1:2. The friction coefficient of partly granulation friction material was higher than the powder friction material, and it also increase along with the temperature rise. The best friction material was made by diameter particle mixed the powder with 2:1, of which particle in diameter of 1-10mm. Without the particle diameter of 1-3mm, the friction material wear rate was lower than when the other diameter levels particle and powder were mixed with 2:1. The wear rate of the partly granulated friction material reduced by 10.9-39.47%, which compared to ungranulated friction material. Furthermore, the friction material that was the mixture of powder and particles, the impact strength will decrease following the increasing proportion. At the same range, the impact strength was relatively large when the particles and the powder was mixed with 1:2. The minimum impact strength was 0.0984J cm2 which the particle diameter was 8-10mm and the ratio was 2:1. The friction material density first increased and then decreased as the particle size increasing. The density whose granules and powders ratio was 1:2 was greater than the density between 1:1 and 2:1 at the same level. The minimum density,which occured in 8-10mm particle friction material, was 1.101659 g/cm3. The hardness of part of the granulated friction material increases as the particles size increases, but the range is limited. The hardness value is 102HRR of the maximum hardness of the friction material, which made with 8-10mms diameter particle and powder that ratio was 2:1, The minimum hardness is 80HRR. The friction material formed by mixing particles and the powder occurred rough surface and obvious porosity and a crack after the abrasion test. When the ration was 1:1 and 1:2, the surface scratched obviously, emerged cutting and furrows. The results showed that when Granules and powder mixed with 2:1, the worn surface of the sample is relatively flat. It also showed the main wear form of the friction material was abrasive wear and fatigue wear.

Effect of mo content on the microstructure and properties of powder metallurgy iron based friction materials

“…Materials with a molybdenum content of 12% have the highest hardness and the matrix is less prone to plastic deformation. The plowing effect between the material and its grinding material is reduced, thereby reducing wear marks and plowing grooves during the friction process [12]. Metal molybdenum particles can provide additional lubrication and reduce friction and wear between graphite and worn surfaces.…”