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Alum Vs. Steel

 

I use 12' 1 1/4" steel pipe to do testing at a power plant. The temperature at this point doesn't exceed 300°F. My boss thinks that if I use aluminum for the same job that the heat would cause the aluminum to expand and the threading on the pipe would become brittle. I am wanting to know if this is true.

Respectfully,

Michael Sharer
combustion technologies - Birmingham, Alabama

You can look up the coefficient of linear expansion for aluminum and see if it looks like it will cause a problem. The issue of the threads becoming brittle can't be addressed without a lot more info about the environment.

I once had a new garage door put in, during an era of cost-reduction programs, and the lock manufacturer had made some of the internal lock parts of aluminum. They warned that only brass keys should be used, but my wife had gone to the hardware store for a backup key before she read the warning, and had an aluminum key made. She put Excalibur into the lock before it was an hour old, and we're still waiting for the King Arthur to come along who can remove it :-)

The point being that aluminum certainly has an absolutely terrible propensity to gall and seize, and your boss will probably be proven right.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey