OFIENGINE: Improvements in maintenance and reliability of marine engines

The manufacturing of exhaust valves, for example, requires materials capable of resisting both extreme conditions of erosion and adhesion of corrosive deposits, as well as the high pressures of the system. The most appropriate material for this type of valve is a Nimonic alloy, although for standard valves, steels resistant to high temperatures and with local hardening at the valve seat are still preferred.

The cost of these materials and the need to optimise the checking and maintenance intervals have given rise to developing effective maintenance and reconditioning procedures for valve components.

The usual procedures involve refilling with estelite through welding at the valve seats and the use of ceramometallic coatings applied at the valve axle using a HVOF (High Velocity Oxy-Fuel) thermal projection technique. While these techniques are included in the specifications of many of the most advanced equipment manufacturers and maintenance companies, their more general use in the manufacture of these components is limited technically and financially.

Technological objectives

The practical targets of the project focus on the following technological aims

• Reduce (in the proportion of two or three times) the maintenance requirements for critical components in marine diesel engines:
  • Exhaust valves: increasing resistance to corrosion and wear of axles and seats.
  • Piston crowns: increasing thermal insulation and resistance to corrosion of the piston crown.
  • Piston rings: enhancing behaviour of piston rings during operation by means of the application of multiple-layer coatings.
    
    
  
  
  
• Reducing by 50% the cost of the process of coating components.
  
  
• Diversifying the technical solutions provided by thermal projection for marine applications by means of increasing the range of materials deposited: from low fusion-point materials, such as alloys of aluminium or copper, to super alloys, carbides and refractory ceramic oxides.
  
  
• Designing and developing of new OFI thermal projection equipment and available for marketing.
  
  
• Manufacturing diesel engine components using OFI technology.
  
  
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