Welding exhaust pipe right off the manifold

[dstig1]

400 series stainless is not "barely stainless". It has key characteristics that make it suitable for exhaust systems - mainly high temp corrosion resistance. It is a very different series than most people think of as SS (the 300's), so it behaves a lot differently than people think when they hear the word "stainless". The OEM exhaust on my wife's explorer finally rotted off at the muffler last summer after 16+ years and 250k miles. That is 400 series SS. I think it did the job just perfectly, especially up here in the salt belt.

Now mind you i have no idea how to weld it properly, but we didn't cover welding those many years ago in the metallurgy classes I took... Should be able to find with a google search or the like.

 

[Mysfyt]

400 series stainless is not "barely stainless". It has key characteristics that make it suitable for exhaust systems - mainly high temp corrosion resistance. It is a very different series than most people think of as SS (the 300's), so it behaves a lot differently than people think when they hear the word "stainless". The OEM exhaust on my wife's explorer finally rotted off at the muffler last summer after 16+ years and 250k miles. That is 400 series SS. I think it did the job just perfectly, especially up here in the salt belt.

Now mind you i have no idea how to weld it properly, but we didn't cover welding those many years ago in the metallurgy classes I took... Should be able to find with a google search or the like.

Well, that's my own terminology. The reason it's used for exhaust in the automotive industry is mostly due to the low cost. But it's way better than the old steel exhaust pipes and mufflers of a couple of decades ago. If you were going to choose the best stainless steel for the application, it would probably be one of the duplex varieties. But economically, it makes no sense to have a perfect exhaust system on a used up car sitting in a junk yard. Cars are measured obsolescence.

 

[dstig1]

Some high end exhausts are now titanium, which is better than the 400 series SS. Saves weight, better corrosion resistance and costs a fortune. 300 series SS wold not hold up as well as 400 series in this application, which is why they use it. I don't think Inconel is a viable option for commuter cars either... Just sayin. The main reason they use 400 series for exhaust is that it holds up to the high temp corrosive environment of an exhaust system. OEM exhausts last a loooong time these days, and that is why. The right material for the job. MY $0.02