16Stingray

Does anyone know what the material is for the exhaust pipes, specifically behind the AFM valves, on a NPP exhaust system?






I believe its stainless steel (might be just steel) but does anyone know for sure? and what type of stainless it is, 304, 316, ect?




Thanks

ErnieN85

It is a low grade stainless (200 series) magnets won’t stick to Higrade and it does to this

16Stingray

would 200 series be weldable to 300 series?

carcrazysammy

No problem. You need to use a tri-mix gas for best results.

ErnieN85

yes, most any muffler shop can do it

16Stingray

I was looking at this blue demon welding wire, has anyone used it?

Since it sounds like i would be welding the stock type 200 stainless steel to the after market type 304 does anyone one know which welding material would be best between these two?

http://www.weldingmaterialsales.com/.../E308LFC-O.htm

http://www.weldingmaterialsales.com/...9/E312FC-O.htm

I wasnt sure on the material but the E312 type says it is capable of joining dissimilar metals. I am not sure if it would be more brittle than the E308.

Any ideas?

16Stingray

bump

ErnieN85

I’m not a an expert welder but it looks like either would work.
Although flux core doesn’t work near as nice as using gas & solid wire.
The best advice I can give is to get some of the material you wish to weld and practice first.

JerryU

The exhaust muffler and pipes are made from 409 stainless. More info than you'll want to know at the end of this PDF!
http://netwelding.com/Muffler_Rust.pdf

409 has been used for mufflers for many years. In fact when I managed an R&D lab for one of the largest welding/gas companies some years one of our engineers had a patent on the welding wire to join it! It contained a small amount of titanium.

It's inexpensive with about 10% chrome and little nickel (0.5%) unlike the 300 series with 18% chrome and 8% nickle. it rusts, just slowly!

It is welded by companies like Tenneco (who I believe make the C7 exhaust system) with a 409 type MIG wire. Most muffler shops use plan carbon steel-it works, just rusts more! Argon/CO2 shielding works OK but best with 8 to 10% CO2 not the normal 25%.

The C7 uses aluminized material that makes it look silver. That has a very thin layer of aluminum coating. It does last longer as outline in the PDF.

In Europe many companies use a better 439 stainless and 307 wire to weld it-both more expensive.

The exhaust pipes in most US made cars are also made of 409 stainless.

ErnieN85

Thanks for your input I was hoping you would spot this & help out

JerryU

Glad I found it! Not sure how- it was in my email!

Seldom look in the tech/performance section as I don't track and those that do don't need my "bench racing" comments!

Now if this was the old days and folks needed to set up a Holley double pumper, know what accelerator pump cam to use on primary and secondary etc etc, I would have useful input!