Material selection

I know, our company brought some of the material from China before. They are all not qualified, although they are really cheap. Do you know any good supplier?
And is anyone can tell me the correct order to polishing? and when does pickling and passivation take into play?

 

skww
If you have bought 316L from china and it's already rusting, it ain't good quality, or what it is. supposed to be.

316L is very suitable for the applications you have shown. The "L" is for welding in sea water applications. Otherwise you'll get carbide precipitation. in just 316. Hence use 316L, which has a lower carbon content.

The pictures you have looks just like poor quality SS, that's all. A gasket or silicon sealant may help further too for additional isolation.

 

skww

I'm no real expert on materials, but I trust most of the stuff I order from Jamestown Distributors ( http://www.JamestownDistributors.com ). They have a pretty good reputation, and they have a customer feedback function on their site. Anyone who allowws you to log on to their site & post feedback on what you've oburght for them (that goes directly into their ad page for that product) gains a lot of respect from me. You can gian lots of info on a product by reading other customers' reviews before you buy it...fewer surprises that way

 

Geee, REALLY?

Whenever You Can, Buy American. Or Canadian. Or European. Anywhere but China.

 

Might want to edit that for clarity...forgot the "/" to terminate the italics, so it didn't parse right

BTW: Anyone know how to delete your own posts (like this one) once they're no longer useful, to avoid clogging up a thread?

 

But I found that most of the rusting are happening at the welded joint. Is it because the filler material or the polishing method? For 316L, what is the best polish method to prevent it from rusting?

 

If it is occuring in way of the weld it is because of carbide precitation. Which suggests that the steel is not 316L but either 316 or 304 or similar.

If all is correct, you could, at geat expense, solution anneal the item. This requires taking the steel to 1050c, where the carbides are in solution and then quench in water.

But is supect the steel is not 316L or if it is, with an approved class cert, must be incorrect filler wire.

 

hmmm, I'd be REALLY tempted to suggest using "Barkeeper's Friend." It's not expensive (about $2 at Wal-Mart...right next to the Comet® scouring powder) and it works GREAT for all the stinless steel in your house (fridge, sink, silverware, etc)...once you have all of the rust gone, just keep it waxed & you should be ok.

I'd also be tempted to wait & see what everyone else has to say, but hey, I don't see where the stuff can hurt

 

Reckon polishing material.. It should be free of residues of other materials, not carbide either or something like that. Don't remember excactly..