Demand for strength in vehicle radiators is increasing throughout the world, as is demand for environmentally-friendly production processes. The brazing technology developed for the manufacture of recoverable copper/brass radiators by Outokumpu Copper Strips is therefore increasingly sought-after, especially in South-East Asia. This environmentally-friendly method requires only moderate investment in new production plant.

An American radiator manufacturer has recently introduced brazing into production on a trial basis.
‘We now intend to refine the method so that it can be used in continuous production’, says Rolf Sundberg, Corporate Metallurgist at Outokumpu Copper Strips at Västerås, Sweden, who is working on brazing development.
The method has been subject to further development and evaluation by the International Copper Association (ICA), as well as Chrysler, Ford, and GM.
‘The evaluation has gone well, and the ICA has reported the test results to radiator manufacturers all over the world, notably Thailand and South-East Asia’, explained Sundberg. ‘We are also working with a number of European manufacturers who are testing brazing methods and the new alloys they need’.
A major truck radiator manufacturer is looking at brazing for the near future, and hopes to use the method in mass production at the end of 1997. Also, a Brazilian firm is planning a new production line for brazing and laser-welding of copper/brass radiators.

Stronger seams
The company claims that brazing produces stronger seams than conventional soft soldering. This means that thinner materials can be used for the fins and tubes, saving manufacturing costs. There is no need to use flux before joining, and the radiator does not therefore need to be washed down after welding.
‘Manufacturers do not need to invest in new furnaces or develop new processes’, Sundberg points out. ‘Furnaces used for hard soldering of aluminium radiators can also be used for copper/brass radiators, and the same goes for other production equipment’.
Brazing uses lead-free solder, so that, unlike aluminium radiators, brazed radiators are 100% recoverable.
‘Our brazing solder has a melting point around 600ÝC, and consists of an alloy of copper, tin, nickel, and phosphorus in powder form, mixed with a metallic binder to form a paste. We have also produced new alloys for the copper and brass components of the radiator in order to prevent loss of strength at high temperatures’, explains Sundberg.

Caption:
Brazing is a lead-free soldering method for copper/brass radiators which produces stronger seams than conventional soldering. The radiators are also 100% recoverable.

For further information please contact:
Anders Falkenø, Technical Manager
Outokumpu Copper Strips
Kopparbergsvägen 28
S-721 88 VÄSTERÅS
Sweden
Tel: +46 21 19 80 00
Fax: +46 21 19 80 41

(Thailand Office)
Outokumpu (SEA) Pte Ltd
22nd Floor Silom Complex Building
191 Silom Rd
Silom, Bangrak
BANGKOK, Thailand
Tel: +66 2 231 36 57/8
Fax: +66 2 231 36 59

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