RVS compound — repair and restoring compound — is a multi-component fine-dispersed mixture of natural minerals, additives, and catalysts.
Depending upon construction and conditions of exploitation of mechanisms treated, RVS can be injected into regular lubricant system of the equipment, into grease or applied directly to open objects.
RVS does not dissolve in oil, does not join chemical reactions with them, does not vary viscosity and is harmless ecologically.
When reaching friction and sliding surfaces of joint machine parts, RVS particles modify themselves and modify friction and sliding surfaces. To facilitate description of the ferro silicate layer formation process, we shall conventionally divide it into stages:
a) Initial state.
- final milling of RVS particles by the peaks of micro relieves on the surfaces of joint parts
- micro relief of contact spots of joint parts cleaning;
- hard autofrettage of RVS finally milled particles in microrelief holes of joint parts contacted surfaces;
- ferro silicate layer formation (performing of the replacement reaction leading to new crystals formation constituting ferro silicate protective layer).
If anyone examines through magnifying lens the friction and sliding surfaces of joint machine parts, he finds out that they are constituted by sharp tops and holes full of wear products and decomposed oils and additives (Pic.1).
When the mechanism is in operation, the load makes friction surface to get into a contact. When done, the tear of protective oil and additive films takes place; and the micro relief elements of the friction surface are being scrapped in contact spot.
Where sharp tops were scrapped, micro flashes take place, destructing oils and additives. These processes lead to dirt getting into oil and into micro relief of friction surfaces.
As the mechanism operates further, more friction act take place and more tops are broken, and even more wear products and other dirt get into the lubricant. (Pic.2)
b) RVS-particles final milling by micro relief tops of the joint parts surfaces.
Micro relief tops of the joint parts surfaces mill RVS-particles in friction zone as teeth of peculiar mill. (Pic.3)
While milling, intensification of micro welding and micro seizing processes takes place, as in places of demolition great amount of energy appears, accompanying by temperature increase.
In local zones of demolition, under the temperature increase up to (9000С -12000С), at the presence of RVS-particles, as a result of micro metallurgic processes almost instantly substitution reaction takes place leading to new crystals formation. That is how the first local areas of ferro silicate (i.e. metal ceramic) protective layers appear on the places of former tops. (Pic.4)
Thickness of these local areas is comparatively small, since at first insignificant number of RVS-particles participate in the process, because their number in friction zone is limited.
In mill process original RVS-particles are milled up to their constituents having defined structure. Beginning from the final mill process of RVS particles, mechanical elimination of dirt from the micro relief gaps of the surface takes place.
c) Micro relief of contact areas of joint machine parts cleaning
Practice has shown that the special structure of RVS micro particles and additives used perform more qualified cleaning of surface micro relief that it can be achieved with modern flushing chemicals which wash away contaminates, but do not clean the micro relief.
While cleaning surface micro relief, a lot of dirt (wear products and decomposed lubricants) earlier pressed and stuck in the holes is removed to the lubricant. Extremely large amount of it may notably decrease effect of RVS-particles hard autofrettage operation. That is why it is very necessary to control oil pollution, and if t is very dirty, it has to be replaced.
RVS micro particles are able to clean micro relief practically from all kinds of contaminants. If cleaning goes in normal mode, within one hour of RVS run-in it is possible to fix changes in the indexes metered while restored equipment is in working mode.
d) Hard autofrettage of fine milled RVS-particles to the micro relief holes of the contacted surfaces of mating parts
This important stage is ensured by absolute cleavage of RVS-particles, by their weak-magnetic properties and their abilities to orientate in the direction of the weakest mechanical resistance.
In every point of friction surface electro magnetic micro fields set up RVS-particles in certain order. Absolute cleavage provides restoration of the particles mutual cooperation powers. And the tops of friction surfaces micro relief while contacting, further on ram the particles (Pic.5).
All this together leads to autofrettage becoming so hard, that is no inferior in respect of hardness to the hardness of the metal on which RVS run-in is performed.
e) Performing of the replacement reaction leading to new crystals formation constituting ferro silicate protective layer
As a result of effective performing of the above stages, more effective wear-protection is brought about, than that could be provided by regular lubricants and additives. Heat generation on the surface decreases, and oil field, although dirty, works more effectively.
Necessary close abutment of RVS-particles (with special additives) to the metal of the contact area surface layer is provided as a result of hard autofrettage. Catalyst's presence in friction process initiates replacement reaction of Mg atoms in RVS micro particles crystal lattices for Fe atoms of metal surface and under-surface layers.
Thus new crystals forming more by volume crystal lattice appear, and they form by their mass a layer, which begins to “rise” over the contact area surface, compensating wear (Pic.6)
Reaching friction zone RVS-particles are being modified on the surface of forming ferro-silicate protective layer and smooth it.
The thickness of the ferrosilicate protective layers depends upon the amount of RVS particles autofrettaged into the holes of surface micro relief, and energy set free during friction and contact (Pic.7).
The thickness of the ferrosilicate protective layers regulates itself: when certain amount of friction energy is set free — ferrosilicate protective layer grows up. The result of ferrosilicate protective layer growth is the compensation of enlarged gaps, which leads to decrease of friction energy generation, and finally to the replacement reaction seizing, i.e. further growth of ferrosilicate protective layer stops.
That is how smoothing of device units friction surfaces takes place, as well as optimization of the gaps in mating parts.
Ferrosilicate protective layer obtained:
- has common crystal frame with the metal, on which it was formed, since it keeps on steel surface much better than chrome, nickel and different weld deposition;
- prevents from hydrogenous wear;
- has the coefficient of thermal expansion compatible to that of steel, with which it has reacted, i.e. does not spall by heating and cooling;
- has high surface micro hardness;
- has low dry friction coefficient;
- has dielectric anticorrosive and heat-proof properties;
- can be renewed as soon as it wears by carrying out additional RVS treatments.
This invention is successfully applied in machine-building and while restoring practically all the types of machine mechanisms units in all the branches of industry, power engineering and transport.