The role of porosity in the dry sliding wear of a sintered ferrous alloy

The role of porosity on the wear behaviour of sintered iron was investigated. Sintered iron was used in preference to steel because the various alloy additions and matrix heterogeneity in the latter might affect the microwear behaviour and the role of porosity. The wear tests were performed in a pin on disc test bed under 10-40 N loads at 0·56 m s-1 sliding speed in air. For the given tribological conditions, it was found that the wear mechanism is delamination or mechanical wear, which is basically similar to that of wrought materials according to subsurface crack generation and crack propagation processes. However, the open pores on the surface act as a site for generation and collection of wear debris. Furthermore, the pores affect the stress distribution and the metal deformation of subsurface layers during dry sliding. Accumulation of the plastic shearing on the subsurface results in nucleation of cracks that further grow by shearing: the fracture process. The propagation of subsurface cracks...

Effects of porosity on delamination wear behaviour of sintered plain iron

The unlubricated wear of sintered iron

Abrasive wear of steam-treated sintered iron

Ashby's map for dry sliding wear of wrought steels has been used as a guide to interpret the dry sliding wear behaviour of PM materials. It has been shown that this map is useful in understanding the acting wear mechanisms and also the experimental wear rates. For given tribological conditions, in terms of normalised pressure and sliding velocity, the sliding wear resistance of PM materials is similar to that of wrought steels, although a closer look at the experimental results highlights the peculiar role of porosity and of a heterogeneous microstructure. In particular, materials with a porosity content of about 10% and with an homogeneous microstructure display the best performances. Since mild wear in metals can be obtained through the formation of protective oxide glazes, steam treatment turned out to be a natural way of increasing the sliding wear resistance of PM ferrous materials. The ‘surface durability’ of steam treated materials was thus shown to depend on the quality of the layer, the a...

G. Guilhot

Papers

The unlubricated frictional behaviour of sintered iron

Surface treatment for iron and steel: Improving the resistance to scuffing, wear, and fatigue by treatment in a non-polluting salt bath