Modification of the Surface by the Method of Friction Plating
Improvement of Metallic Items’ Service Characteristics due to Modification of Their Surface by the Method of Friction Plating
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
8 Project completed
Senior Project Manager
Alexandrov K A
MISIS (Steel and Alloys), Russia, Moscow
- VNIIKhT (Chemical Technology), Russia, Moscow\nAO Kompozit, Russia, Moscow reg., Korolev
- "Hatch" Corp., Canada, ON, Mississauga
Project summarySheridan Science & Technology Park, 2800 Speakman DriveGlobal problems of the third millennium - saving in metals, resource saving and ecology are directly connected with creation of new materials. Surface and surface layers, which could be considered as a peculiar composite with a particular complex of physical and mechanical properties, play therein the decisive role. The surface of a product is in the first place subject to all detrimental attacks. Just the surface layer determines to a considerable extent strength, tribological and anticorrosion properties. State of the surface and its adhesion properties are determining in processes of production of composite materials (CM).
One of effective ways of improvement of service properties of metal products is application of protective coatings possessing high corrosion resistance, hardness, wear resistance and other properties. Serviceability of the products is much influenced by strain strengthening of the surface layer. In some cases it's possible to combine processes of application and strengthening. It seems advisable to create materials with principally new properties in surface layers or apply a composite material prepared in advance to the surface of a product as a coating.
As a result of analysis and generalization of available works and our preliminary researches is outlined a new promising way of science of materials as concerns protection, strengthening and modification of the metal surfaces, namely: plastic deformation of the surface layer combined with application of coating with flexible tool. Rod, strip etc. as a coated material (CM) is pressed with a certain force to the rotary wire brush (RWB) as a flexible tool. In the contact zone the CM is heated to a high temperature. The particles of the CM are grabbed by ends of the wires of the flexible tool and carried onto the worked surface. At the same time the product's surface is conditioned and heated and there is combined plastic deformation of the surface layer and particles of the CM, which causes strong adhesion of them with the base. Different metals and alloys or specially created composite materials could be used as a CM. It makes possible to form surface layers with principally new complexes of properties. The examined method of creation of new materials is called frictional plating (FP). Its comparison with conventional methods of protection, strengthening and modification of the surface shows that under some conditions the FP method has a number of advantages: low specific quantity of metal and energy-intensity, absence of complicated operations of preliminary preparation of the surface being harmful for attending personnel, high efficiency and capacities of the process as well as its ecological purity.
Main directions of development and prospects of the use of the FP method in creation of new generation materials should be noted:
One of the principal problems of new machine building is increase in wear resistance and lowering energy intensity of moving parts. Requirements for friction units could be the most fully met by use in them of CM which could be applied to the surface of tribological mating by FP method.
Of interest are studies of elimination of porosity of plasmasprayed coatings by application of additional coat layer by FP method.
Researches concerning subsequent laser and heat treatment of coatings applied by FP method are of great practical importance and request for further development. Multilayer and multicomponent coatings could be particularly effective in this case. That is a way of creation of new class of heat-resisting materials.
There is a possibility of application of perse metal and alloy coatings on glass, ceramics and so on by FP method. Its possible as well to apply ceramic coatings on metallic surfaces, which allows to create new materials with improved service characteristics.
The FP method makes it possible to create a texture in surface layers and local areas of the surface of products, which allows for improvement of service properties of materials.
It should be noted in conclusion that the examined FP method is one of the ways of creation of new generation materials. It's insufficiently known and represents a peculiar "niche" for scientific researches. Hence follows the urgency of complex work in theoretical and experimental study of the resource-saving and ecologically pure FP process.
AIM OF THE WORK. Elaboration of theoretical and technological principles of the process of plastic deformation of surface layer combined with application of metallic coatings with flexible tool (friction plating- FP); creation of resource-saving and ecologically pure technologies for production of metal products with improved service properties.
To attain the set aim the following tasks were formulated:
- develop the mathematical model of the process of thermoplastic deformation of surface layer;
- fulfill a complex of metallographic and other experimental studies to reveal mechanisms and properties of deformation of the surface layer, mechanism of its formation and application of coatings, influence of working by FP method on physical and mechanical properties of materials;
- designing new processes of strengthening and protection of metal surfaces, development of new equipment for application of coatings and pre-coating by FP method in production of clad metal products;
- determination of prospects of further development of the FP method and creation of new technologies.
The main expected results are following:
- Method of producing (method of deposition of) friction-resistant coatings to lower wear of friction couples which should allow to raise service life of parts by 1,5 to 3 times;
- Method of restoring the sizes of worn parts (hydraulic cylinder rods, interference connections etc.);
- Method of producing (method of deposition of) coatings on mated surfaces of interference connections to increase their bearing capacity by 1,5 to 2 times and to avoid fretting corrosion (wheel pairs of the railway transport, sleeved rolls, screw propellers);
- Increase in endurance limit (by 30 to 40%), fatigue strength and service life of machine parts by working their surface by FP method;
- Method of producing (method of deposition of) protective coatings on long products to raise their corrosion resistance;
- Method of combining operations of surface conditioning and application of pre-coating by FP method in production of clad metal products to improve the bond of components, lower the energy and power parameters of the rolling by 10 to 15% and improve the service properties of finished products.
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