Contract 166(304) – finalized - MATNANTECH Program

NEW MATERIALS DESTINED TO ACCOMPLISH AND COAT BALL BEARINGS OSCILLATING BLOCK

PARTNERS: INCDT COMOTI Bucharest INOE 2000 Bucharest SC MOLDOSIN SA Vaslui SC PETROSERVICE SA

Project’s goal is coming up with  „new materials destined to accomplish and coat ball bearings oscillating block”

High Speed Angular Bearings (LRTR) have three normal functioning characters of service: the initial one in witch the speed is increasing gradually, the stable regime functioning in nominal parameters and the stopping regime, in witch the speed is decreasing. This is important because it induces distinct characters of service, with various problems, that can be shown by the testing and diagnosis installation of the LRTR.

The optimum constructive form for making a high speed angular bearings for equipping turbine installations is the “oscillating blocks” form. Main characteristics of the bearings (lifting force, friction moment and temperature, minimum thickness of the lubricant layer, etc.) are given, if the mechanical processing is done well, by the characteristics of the material the bearing is made of, including the oscillating blocks.

Materials for oscillating blocks must satisfy some difficult and somewhat contradictory demands, high level of thermal and mechanical variations being the main element to be considered.

The bearings we worked on during this project are under subject to a dynamic stress and also, under pronounced fatigue effect.

The stress that the oscillating blocks material is subjected can be described:
· mechanical stress = contact pressures, fatigue, extreme overload
· thermal stress = in bearing friction and due to the heat resulted in combustion process
· chemical attack = due to lubricant
· wear effects = due to relative motion of the bearings surface
· contaminants substances and foreign micro particles effects.
· electrostatic stress
· radiation exposure

In our country, for making oscillating blocks, in present are used various types of bronze or copper alloys, but this alloys do not meet the requirements mentioned above resulting in bearings not being able to function for higher performance.

INCDT COMOTI, with it’s experience in turbine machines construction has tested and tried various types of alloys and decided to make and certify within this project a new advanced, complex copper based alloy with special inputs under a strict control realized in special melting conditions.

In order to meet all the demands, INOE conceived and tested a new coating material and a new application technology that improves greatly bearings specifications.

The approached domain is coating layers with capabilities of thermal mechanics, wear, corrosion, working in the same time as a superior lubricant. The domain is one of the latest and it’s aimed to implement new environment friendly, high efficiency technologies with low energetic consumption, in order to offer the produced composite system, base material – applied layer special properties. Active environment – plasma, in the presence of which the layer material’s synthesis reactions occur, is a way to induce reactions that cannot happen in equilibrium conditions, since the capability to synthesize unique materials, not available through classic procedures. Choosing the applied material depended on compatibility with the under-layer and the lubricant capabilities.

Within the project, it has been applied on the base material(object of prior research) (complex copper based alloy) various types of under-layers (In-Sn and Ag), finding the composition and characteristics of the layer with best properties.

Bearings were made within the project, witch were tested and certified in static regime, according to a technology accomplished on an installation made also within the project.

The project was finalized with certification of bearings in normal functioning conditions (in production), accomplished on air turbine machines and methane gas turbine machines.

Project placing:
Test bench – INCDT COMOTI Bucharest
High Speed Angular Bearings :
- supercharger S.P.Ticleni
- air compressor PETROMSERVICE  - Suplacu de Barcau

Projects results:
· accomplishing a new, advanced material for oscillating blocks manufacturing as parts of the high speed angular bearings;
· accomplishing a new material for surface coating of high speed angular;
· accomplishing a new technology for surface coating of high speed angular bearings.