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ADVANCED MATERIALS AND BRAZING FILLER METALS IN VACUUM BRAZED HEAT EXCHANGERS

Objective


Through target orientated research work, the consortium has developed a new nickel based filler metal alloy which pocesses very good casting, mechanical and corrosion properties. The filler metal is applicable in both ammonia and chlorine rich environments.
The manufacturing of amorphous foils by the rapid solidification process has been optimised in order to achieve wide homogeneous foils with the demanded properties. Also, the brazing cycles for joining advanced materials by brazing in vacuum furnaces have been optimised. This has resulted in elaboration of a lager number of brazing cycles which are directly applicable for joining the materials investigated.
Moreover, the construction and design of the pressing tools for pressing sheets of foil for compact plate heat exchangers have been re-designed in order to meet the demands from the materials involved.

Finally, an extensive testing programme has been performed to acquire mechanical and corrosion data of a number of materials combinations. For acquiring these important data, special designed specimens have been used for evaluating single brazed crosspoints which represent joints from compact brazed plate heat exchangers. The outcome of the work is an extensive data base which is applicable in general for joining parts by brazing in many sectors of industry.
The proposal project is directed at expanding the range of applications in which it is possible to use the highly efficient compact brazed heat exchangers. In particular the environmentally conditioned substitution of freons with more ozone friendly gases demands substitution of the presently used copper filler metal with filler metals with much better corrosion resistance. Based on the most recent research in nickel based filler metals the project will :

- Develop new filler metals with improved mechanical and corrosion properties compared to commercially available filler metals.

- Develop a industrially feasible method of applying the filler metals onto the heat exchanger plates prior to brazing.

- Demonstrate the found solutions by brazing prototype heat exchanges and testing them.

Upon achieving the objectives it is foreseen that the amount of material tied up in heat exchangers in new applications can be reduced with from 30-80 % wiht superior heattransfer data and competitive prices.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

AS INDUSTRIHAERDERIET
Address
Herlev Hovedgade 15
2730 Herlev
Denmark

Participants (5)

AACHEN UNIVERSITY OF TECHNOLOGY
Germany
Address
Jülicher Str.344a
52056 Aachen
RISO NAT. LABORATORY
Denmark
Address
Frederiksborgvej, 399 (P.o. Box 49)
4000 Roskilde
SWEP INTERNATIONAL AB
Sweden
Address
Bavergatan, 9 (P.b. 49)
26122 Landskrona
TU DENMARK
Denmark
Address
Building 425
2800 Lyngby
VACUUMSCHMELZE GMBH
Germany
Address
Grüner Weg 37
6450 Hanau