Joining dissimilar metals
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Joining dissimilar metals
I know might be making more out of this than it needs to be, but I was having a conversation with one of our material experts the other day about welding dissimilar metals (SS to carbron steel, titanium to SS etc) and a lightbulb went off in my head.
Many of us use titanium test pipes with stainless exhausts and those are obviously joined in some fashion. Has anyone ever heard of a corrosive reaction triggered by the chemistry of the metals? What kind of hardware would you use to join the two? SS, Ti, zinc?
Crazy, I know...but humor me
Many of us use titanium test pipes with stainless exhausts and those are obviously joined in some fashion. Has anyone ever heard of a corrosive reaction triggered by the chemistry of the metals? What kind of hardware would you use to join the two? SS, Ti, zinc?
Crazy, I know...but humor me
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it's (galvanic corrosion) not enough to worry about. If you use zinc to fasten the two together, that'll be the first thing that corrodes. But unless you're driving a lot on salty/wet roads, you won't have any issues.
Just use stainless fasteners and call it a day.
Just use stainless fasteners and call it a day.
#4
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Well, if you have a Ti testpipe and SS downpipe, there should be a gasket in between them. Usually gasket material is some type of composite.
Also, I would stay clear of SS fasteners on exhaust components. SS fasteners are not ideal for high temp applications as they will gall.
Also, I would stay clear of SS fasteners on exhaust components. SS fasteners are not ideal for high temp applications as they will gall.
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Well, if you have a Ti testpipe and SS downpipe, there should be a gasket in between them. Usually gasket material is some type of composite.
Also, I would stay clear of SS fasteners on exhaust components. SS fasteners are not ideal for high temp applications as they will gall.
Also, I would stay clear of SS fasteners on exhaust components. SS fasteners are not ideal for high temp applications as they will gall.
plus your mounting hardware will set up a conductive path between the dissimilar metals, the gasket won't be enough by itself.
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yes, cats get very, very hot and could very well pose a problem for stainless. I've had trouble with carbon steel bolts on cats, but never had issues with stainless on test pipes where it connects to the dp or catback. It's a matter of picking the lesser of two evils, galling or rusting. Both can lead to having to cut the bolt or strip the crap out of it till you can muscle it off. Carbon stell will be the anode compared to stainless, so that will make them rust even faster than normal.
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...hmmm...and here I was thinking that I am the only one that ponders such issues. From what I understand by people's comments there is no "safe" solution and one has to choose something, one way or another. I think SS fastners are the way to go, understanding of course that they present certain limitations like any other solution (carbon steel, zinc etc).
Good stuff people, we have some serious scientists on here, hehehe.
Good stuff people, we have some serious scientists on here, hehehe.
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the reason stainless steel gall/cold weld is because it is too squeeky clean. A very light coat of lithium grease, moly disulphide, copper/nickel anti seize will prevent that. WD40 is too light, gets washed out or evaporates with heat.