Friction and wear behaviours of surface densified powder metallurgy Fe–2Cu–0.6C material

Abstract

Surface rolling was employed to fabricate a densified layer on a powder metallurgy (PM) Fe-2Cu-0.6C piece. A densified surface layer with a depth of 335 μm and a surface hardness of 330 HV 0.1 was obtained, in which the lamellar spacing of pearlite and grain size of ferrite were refined. Friction and wear behaviours of the surface densified material were studied. Results indicated that friction coefficient of the rolled material decreased as the load increased, which was lower than that of the un-rolled material. Wear volumes were lower than that of the un-rolled material, which increased as the load increased. Wear loss was caused by flake spalling and grooves, and the wear mechanism mainly was abrasive wear. The surface densified layer with higher hardness and lower porosity can hinder the cracks initiation and propagation on the surface and under the surface, which enhance the wear resistance of the PM material.

Effect of Carbon Content on the Properties of Iron-Based Powder Metallurgical Parts Produced by the Surface Rolling Process

“…This indicates that the addition of carbon improves the friction performance of the densified layer in PM parts and is conducive to extending the service life of parts in actual working situations. The surface-densified layer, with relatively high hardness, could hinder crack initiation and propagation on and under the surface and enhance the wear properties of the PM material [6].…”

“…Compared with forging, the advantages of the PM process are that it is suitable for complexly shaped parts, the raw material utilization rate is high, and the production cost is reduced [3,4]. However, the inherent porosity in traditional single pressed and sintered products is one of the major factors causing reduction in the mechanical properties of PM parts [5,6]. Although new advances in powder metallurgy such as hot isostatic pressing (HIP), selective laser melting (SLM), and high-velocity compaction technology are used to manufacture high-performance components with homogeneous high density, the facilities required for these processes are more specialized and the production costs are higher compared with those of the surface rolling process [6][7][8].…”

“…Therefore, in order to expand the application field of PM parts, surface densification is a cost-effective and highly precise method enabling the surface of parts to be densified, while still keeping the internal porous state. Surface densification can greatly enhance the mechanical properties and surface properties of PM parts while retaining the advantages of powder metallurgy; specifically, maintaining the light weight and damping capacity of PM parts [6][7][8][9][10].…”

“…However, the inherent porosity in traditional single pressed and sintered products is one of the major factors causing reduction in the mechanical properties of PM parts [5,6]. Although new advances in powder metallurgy such as hot isostatic pressing (HIP), selective laser melting (SLM), and high-velocity compaction technology are used to manufacture high-performance components with homogeneous high density, the facilities required for these processes are more specialized and the production costs are higher compared with those of the surface rolling process [6][7][8]. Therefore, in order to expand the application field of PM parts, surface densification is a cost-effective and highly precise method enabling the surface of parts to be densified, while still keeping the internal porous state.…”

The Effect of Rolling Temperature on the Microstructure and Mechanical Properties of Surface-Densified Powder Metallurgy Fe-Based Gears Prepared by the Surface Rolling Process

“…Those studies indicated that a densification depth of 0.2-1 mm was formed on the surface layer with an obvious increase in density and surface hardness. The fatigue and wear resistance of the PM gears treated by surface densification can also be enhanced [16,17]. These reports emphasize the increased performance after rolling, although few address the warm rolling surface densification process on PM materials.…”