Are Stock (OEM) Duramax exhaust manifolds Cast Steel or Cast Iron

[MattKatz]

I'm getting read to weld the V-bands on today and did a quick search and couldn't find the answer. Does anyone know if these are Cast steel or iron. The Manifolds I am using are the Kodiak Manifolds as well, if it makes a difference. but I would think not. I know the LS OEM Manifolds are a cast steel and weld nice, but wasn't sure on these just buy looking at them.

If anyone knows for sure, that would be awesome. Thanks :thumb:

 

[2004LB7]

Almost nothing is cast "iron" anymore. All of it has some percentage of carbon in it making it "steel".

As to the amount of carbon added that would be anyone's guess. What about spark testing it?

 

[WVRigrat05]

Cast steel. I had to heat mine to weld a bung in my LLY.

 

[WolfLMM]

Machines like steel, really crappy steel.

 

[MattKatz]

YEah I spark tested it and it seemed to test like a mix of steel and iron, Cut Clean with my band saw and we tacked the Vbands on last night with SS Filler....Seemed pretty easy to tack up without preheat. We've never run a bead on something like this so when its time we will probably heat the pieces with a torch for the preheat and see how it welds up, But I think itll be fine. I was thinking it was steel....Thanks for the replies guys, I was just curious if anyone knew for sure. :thumb:

 

[MarkBroviak]

Grey cast iron I believe is the official name of it same as the Vgt turbine housing. Definitely preheat and let it stay hot and slowly cool down. We use an oven to weld them without issues.

 

[WVRigrat05]

We heat all our cast matieral to a minimum evenly distributed 350 degrees. Weed burner or a rose bud works good if it's all you have handy.

 

[testdrive]

Grey cast iron I believe is the official name of it same as the Vgt turbine housing. Definitely preheat and let it stay hot and slowly cool down. We use an oven to weld them without issues.

Mark is correct. In fact it is mostly likely what is classified as a 20,000 lb grey iron, in other just plain old cast iron. The same as man hold covers. If it were cast steel or ductal class they would be much higher in cost. In general cast steel often requires heating treating after casting.

 

[PaIronHead]

Cast iron is minimum of 500 degrees and cast steel is minimum of 250 degrees and don't let it get over 350 degrees after a pass for cast steel. That's running 7018. You can weld it without Pre heat and they call for 100 degrees to take moisture out of iron and weld 1 inch at a time and peen the weld.


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