Which is the best stainless steel for a muffler, 304 or 409? Flowmaster
offers both on their Hushpower II series with a $30 price difference.

Doc Custer
Retired Software Engineer and sometime Audiologist


304 is Austenitic better corrosion resistance higher temp
and 409 is Ferritic lower cost.

"The presence of chromium greatly improves the corrosion resistance of the
[Austenitic] steel by forming a very thin stable oxide film on the surface,
so that chromium-nickel stainless steels are now the most widely
used materials in a wide range of corrosive environments both
at room and elevated temperatures.

Added to this, austenitic steels are readily fabricated and do not
undergo a ductile/brittle transition which causes so many problems
in ferritic steels. This has ensured that they have become a most
important group of construction steels, often in very demanding
environments."

http://www.key-to-steel.com/Articles/Art104.htm

Paul Lamar ...No rotor no motor.

We use 321 stainless tubing for the exhaust on the Yak racer. It is an
aircraft grade and has proven very good exhaust material. You have to use
347 filler wire, and do a very good argon purge on the inside of any part
you are welding on. This process gives very reliable exhaust parts.
We get our tubing and filler rod from Burns Stainless. If you ask for
"blemished" bends, you get tubing with cosmetic flaws at a much cheaper
price.
Larry


The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.