[RanGer498]

I found this on the net and decided to post this as a FYI just incase people are wondering the difference between T409/T304 stainless steel.


"From: Normand Moreau <nmoreau@videotron.ca>
I did a little search on the web for T-409 vs T-304 stainless steel. I
found a very simple comparative FAQ at the address :
Inter.net Canada : the alternative to large telecommunications companies
You can find a lot of detailed informations on the web about that subject.
This one is very concise.

Why 409 type Stainless Steel pipes and shells?
409 type Stainless Steel is specially designed for automotive exhaust
systems.
409 type Stainless Steel resists atmospheric and automotive exhaust gas
corrosion.
409 type Stainless Steel developes a light surface discoloring which will
retard progressive corrosion.
409 type Stainless Steel contains 10.5%...11.75% Chromium
Why 304(14G) type Stainless Steel tips, flanges, internals and brakets?
304 type Stainless Steel contains 18%...20% Chromium and 8%...10.5% Nickel.
304 type Stainless Steel has excellent heat, oxidation and corrosion
resistance.
304 type Stainless Steel Looks great and will shine for ever!
How to clean Stainless Steel .
409 type Stainless Steel can be cleaned with non metallic pot scrub pads
and soap, ammonia, liquid or powder detergent.
304 type Stainless Steel can be cleaned with non metallic non abrasive
cleaning pads or brushes with soap or liquid detergent, use "Chrome polish"
if necessary.
Do not clean with Steel Wool or a Steel Brush --->
surface rust will result.
*************
The most common stainless steel used by muffler shop is the T-409. Borla
use T-304 stainless steel grade. It's why the price is so different. A
Borla looks great and will shine for ever!
T-409 is good for peoples who live where there are no calcium or where the
corrosion is not a problem.
T-304 is for north american and canadian peoples who want to keep their
cars for more than 3 years in a corrosive environment"

[RanGer498]

409 stainless is a blend of stainless and mild steel. This type of stainless is used to make production catalytic converter assemblies that have a 100,000 mile durability requirement. 409 stainless has excellent forming characteristics and is rust through resistant. 409 stainless will develop a light surface rust.