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Stainless steel vs. aluminized steel for heat exchangers

I am presently investigating high efficiency gas furnaces and would appreciate an answer to my question: Which material is better as the heat exchanger - aluminized steel or stainless steel?

Jack Holowatch
- Mississauga, Ontario, Canada
2003

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Depends on what parameter(s) you use for "better".

Aluminised steel has higher thermal conductivity than most stainless steels which might be "better" in a heat exchanger, but it also has lower corrosion resistance which might be "worse". Then there are dozens of different stainless steels which have different corrosion-resistance characteristics as well as different thermal conductivities.

Depending on actual temperatures and atmospheres, heat-resistance might be important. That could be heat-resistance as in resistance to surface scaling through oxidation, or heat-resistance as in resistance to degradation of mechanical properties through metallurgical phase changes.

Mechanical properties would also be relevant if you are looking at high gas velocities.

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.
2003