TESTS OF THE METAL-TO-METAL ACTIVE SYSTEM

The results of systematic tests of friction pair steel 45 / polymer Ф4-ВМ under sliding are given below.

The curve of limiting states of friction pair (sliding fatigue)

Curve AB (Direct Effect) :  Curve CD (Back Effect) :

Special type of a limiting state – surface plasticity waves, which are found in E part of the diagram (σ_a=1,2 σ_-1)

Distribution of microhardness along the rolling trail L

Microtopography of surface damage under rolling friction (vertical column of drawings), under wear-fatigue tests (other drawings) and the dependence of depth h of the damaged layer on the amplitude of cyclic stresses σ_a under contact pressure ρ₀=const

From this data, it follows that :

1. Large pittings are formed under rolling friction, they do not occur under wear-fatigue tests.

2. Superposition of the fields of contact and bending stresses causes energy to be expended mostly on fine chipping of grain fragments and their separation than on penetration of damage into the material.

3. Fine wear of the surface layer under rolling-mechanical fatigue exposes a new, relatively intact surface with a higher resistance to fracture. This leads to a significant increase of the life of an active system (in comparison with the life of analogous friction pair).