Stainless steel corrosion

[mbalbritton]

So, who knows about Stainless Steel (304) corrosion due to Chlorides or maybe something else chemical wise that might be found in a pool setting? Take a look at this corrosion and give me your guesses as to WTF is going on. this is a threaded rod of 304 SS that has been submerged in basically pool water for about 6 months.

 

[jeepinmatt]

304 stainless is stainless in name only. It has poor corrosion resistance compared to "good" stainless like 316. Also the fact that it is threaded gives a lot more pointed surfaces to easily corrode. Beyond that I have nothing useful to add without just googling for you.

 

[ghost]

When I work in the photo lab industry we saw Stainless tanks corroding all the time. I would guess its the chlorine in the water. What other chemicals are put in pools?

 

[braxton357]

I've never seen 300 series stainless oxidize like that. Is it a saltwater pool? Proper equipotential ground? Looks like it turned into an anode somehow

 

[RatLabGuy]

I've never seen 300 series stainless oxidize like that. Is it a saltwater pool? Proper equipotential ground? Looks like it turned into an anode somehow

This is what I'm thinking. Stainless can corrode but that fast, and this style looks like an electrolysis effect.

 

[WARRIORWELDING]

Not all stainless is equal. That's the short answer. My question before it turned to poop would have been? How magnetic was it?

 

[mbalbritton]

I don't have the answers to what all is in the water. this is in an attraction in Italy. What I'm also looking at in the photo are the SS nuts at either end of the threaded rod. I'm wondering if someone fuckt up and didn't use SS to be honest.

 

[jeepinmatt]

Silver zinc looks a lot like stainless to someone who doesn't know or care

 

[mbalbritton]

Silver zinc looks a lot like stainless to someone who doesn't know or care

The thing is, we don’t order mild steel at all. So there shouldn’t be any in the shop.

 

[Ron]

is it possible that isnt corrosion and is instead an algea or fungal growth?

That if you took a rag and wiped itd come clean?

Only asking because you say its a continent away and such

 

[Ron]

Is it a saltwater pool?

Wouldnt matter. Saltwater pools just use salt to make chlorine through their chlorinator. The water in the pool is identical (assuming both systems are installed set up right)

 

[braxton357]

Wouldnt matter. Saltwater pools just use salt to make chlorine through their chlorinator. The water in the pool is identical (assuming both systems are installed set up right)

Yes but they literally use electrolysis to create the chlorine, that rod looks a whole lot like a nasty anode.

 

[RatLabGuy]

Silver zinc looks a lot like stainless to someone who doesn't know or care

This was my first thought, followed by, giving them the benefit of doubt and suspecting some electrochemistry facilitating the reaction

 

[rockcity]

Maybe use 316L and see if it doesn’t any different. If it’s the same, you certainly have electrolysis/anode issues.

 

[awheelterd]

Looks like some of that Chinesium stainless :

 

[benmack1]

It’s got covid.