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LASER TREATMENT AS A TOOL FOR TAILORING THE SURFACE COMPOSITION OF ALLOY COMPONENTS FOR ENGINEERING APPLICATIONS

Objective


In this project, laser surface treatment processes have been developed that produce higher quality coatings for steam and gas turbine components, improving their resistance to erosion and corrosion.
PREVIOUS STUDIES ON SIMPLE FLAT SAMPLES HAVE SHOWN THAT SURFACE STRUCTURES AND COMPOSITIONS WITH UNIQUE PROPERTIES CAN BE PRODUCED BY LASER SURFACE-ALLOYING AND -CLADDING.

THE MAJOR OBJECTIVES OF THE PROJECT ARE TO FURTHER DEVELOP BOTH THE APPLICATION TECHNIQUES AND THE COMPOSITION AND STRUCTURE OF THE SURFACE ALLOYS TO ALLOW PARTS OF MORE COMPLEX SHAPE TO BE WELDED.

THE AIM OF THE RESEARCH IS TO IMPROVE THE CURRENT LIFETIME OF 100.000 AND 200.000 HOURS FOR STEAM AND GAS TURBINES RESPECTIVELY BY AT LEAST 50 % BY DEVELOPING SURFACE ALLOYS AND CLADDINGS WITH GREATER EROSION-, FATIGUE-, AND WEAR-RESISTANCE THAN THOSE CURRENTLY AVAILABLE. A FURTHER AIM IS TO OBTAIN AN INCREASED EROSION AND STRESS-CORROSION CRACKING RESISTANCE IN THE ORDER OF 50 % TOGETHER WITH A REDUCTION IN TEMPER EMBRITTLEMENT AND RESIDUAL STRESSES FOR COMPONENT SHAPE.

FOR NEXT GENERATION OF STEAM TURBINES DESIGNED FOR HIGHER EFFICIENCY AND GREATER ECONOMY, THE BLADE LENGTH OF THE LAST BLADES MUST BE INCREASED BY 30-35 % CORRESPONDING TO AN INCREASE BY 50 % AT THE STEAM PASSAGE SECTION WHICH NECESSITATES THE USE OF CLADDED TITANIUM ALLOY BLADES INSTEAD OF CLADDED STEELS. THE MINIMUM GOAL IS TO ACHIEVE THE SAME STATISTICAL LIFETIME OF THE TITANIUM BLADES AS CURRENTLY OBTAINED FOR THE SMALLER CLAD STEEL BLADES.

THE EMPHASIS WILL BE ON (I) THE FORMATION OF EROSION RESISTANT CLADDINGS ON STEEL AND TITANIUM SUBSTRATES FOR USE ON THE NEXT GENERATION OF STEAM TURBINES; (II) NON-EQUILIBRIUM SURFACE ALLOYING OF NICKEL BASED ALLOYS FOR GAS TURBINES AND (III) THE FORMATION OF AMORPHOUS SURFACE LAYERS ON ALUMINIUM SUBSTRATES TO IMPROVE BOTH THIR WEAR AND CORROSION RESISTANCE.

FOR THE LATTER PURPOSE, THE EFFECTIVENESS OF CO2, ND-YAG, COPPER VAPOUR AND EXCIMER LASERS IN PRODUCING THE DESIRED SURFACE ALLOYS WILL BE EVALUATED. IN ADDITION, NDT TECHNIQUES FOR QUALITY CONTROL WHICH ARE CURRENTLY USED FOR TESTING WILL BE ADAPTED FOR APLLICATION TO EVALUATION OF LASER PROCESSED SURFACES AND PROTOTYPE TESTING EQUIPMENT WILL BE DESIGNED.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Metallurgical Industrial Research andTechnological Development Center SA
Address
Industrial Area
38500 Volos
Greece

Participants (7)

ALSTOM UK LTD.
United Kingdom
Address
Mill Road
CV21 1TB Gawston Rugby
ATV Korrosionscentralen
Denmark
Address

2600 Glostrup
Compagnie Générale d'Electricité (CGE)
France
Address
Route De Nozay
91460 Marcoussis
FORCE INSTITUTE
Denmark
Address
345,Park Alle 345
2605 Brondby
Foundation for Research and Technology-Hellas
Greece
Address

71110 Heraklion-crete
MAN Technologie AG
Germany
Address
Dachauerstraße 667
80995 München
United Kingdom Atomic Energy Authority (UKAEA)
United Kingdom
Address
Culham Laboratory
OX14 3DB Abingdon