Stainless vs zinc hardware

[PoorOwner]

So if I use a steel threaded rod and a SS nut as a jam nut, is that going to corrode and fall off?

sometimes you just ended up mixing it not knowingly or just simply what you have on hand.

 

[nbpt100]

all depends on application and do NOT mix materials, then you are asking for issues in most cases. 90% i use zinc steel, few places where recommended or exposed i use SS.

Automotive i use the Gr 5 or 8 depending on loading

Can you enlighten us on this? I am well familiar with two metal corrosion. I assume that is what you are referring to with using two different materials. It comes down to the difference in the electro negativity differences beween the two metals in contact. It has been a long time since I had to think about this.

I know plating like galvanizing act as a sacrificial anode and the zinc gets eaten before the steel.
I am not sure there is enough of a difference between Carbon steel and stainless steel. I would have to dig up one of my old college books and look it up.

I have used St. St. nuts on steel muffler clamps many times and it has been a help vs. a problem. If I ever needed to undo the clamp I could get the nuts off with out any big deal. If I use the plated Grade 5 there would have been a good chance it would be a struggle to get them off.

I am always open to learn something new.

 

[Iroc-Z]

Not a fan of stainless hardware for standard use. When I worked on boats that's all we had and it was really weak material. I am building up my hardware selection and am sticking with grade 8 zinc coated or black oxide. It does cost more but I am slowly buying from McMaster Carr once a month.

 

[Lonnies Performance]

You can mix fastener grades, but keep in mind the connection is only as strong as the weakest fastener. Remember every engine has threads in it... they are typically cast iron or aluminum & you are using steel or stainless bolts on it. It is done every day.

There also can be some galvanic action between 2 different materials, so anti-seize is always a good idea.

I had the stainless galling issue when I put new headers on my Camaro & used stainless nuts/bolts on the collectors. A few months later I could not get them apart... the car never even got wet in that time period. Had to break all 6 bolts off. Replaced with stainless bolts/brass nuts & all is good.

 

[Iroc-Z]

You can mix fastener grades, but keep in mind the connection is only as strong as the weakest fastener. Remember every engine has threads in it... they are typically cast iron or aluminum & you are using steel or stainless bolts on it. It is done every day.

There also can be some galvanic action between 2 different materials, so anti-seize is always a good idea.

I had the stainless galling issue when I put new headers on my Camaro & used stainless nuts/bolts on the collectors. A few months later I could not get them apart... the car never even got wet in that time period. Had to break all 6 bolts off. Replaced with stainless bolts/brass nuts & all is good.

Ran into that all the time with stainless. Especially if you used power tools to tighten them.