One for The Experts

By ctacker (****)

Date 11-16-2007 02:55

sounds like thats one for the experts to answer :)

By js55

Date 11-16-2007 14:35

It doesn't hurt, and it could help minimize a bit I suppose (though SS brushes ain't cheap), but keep in mind that as soon as the SS brush contacts the CS side of the joint (like down in the bevel-so how do you avoid it) its contiminated. So if you are going to maintain control you're going to have to be tossin brushes one after another.

By ZCat

Date 11-16-2007 16:01

that's why I was wondering, the contaminating the brush thing. does a 309 weld rust if you buff it with a carbon brush?

By js55

Date 11-16-2007 16:25

You know, thats a very good question. And I've never asked, nor seen it asked that way.
The answer I would have to say is still yes however, because there will always be, even if its brand new, some Fe oxide on the brush, the rust would be greatly minimized as opposed to a brush that has been contiminated with Fe oxide from CS base metal.
Its the oxide and not the Fe. SS has lots of Fe in it-it is a ferrous material. ~70% to 75%.

By graveyhog (*)

Date 11-16-2007 16:59

No ! The HAZ will rust before the weld will.Just use the same brush you started with to brush the 309 weld and don't use it on stainless material after you have used it on the stainless to carbon.Have one carbon brush,one stainless brush,if you are welding other stainless material like 316,308,etc.dont use it on the 309 material.You use the same brush on carbon material and on the Bi-metal weld.I Would use a brush that has stainless wire on the brush.I have welded hundreds of these type welds in power house plant's.I would use a stainless wire brush,but I also had another stainless brush for stainless material only.Just mark them up.I hope I have not confussed you.

By ZCat

Date 11-16-2007 18:23

not at all

By dmilesdot (**)

Date 11-16-2007 19:30

Back in my nuclear days, I recall a study done by Southwest Reseach that determined that other than the staining there wasnt any harm done to the Stainless by contact with Carbon Steel.

By Tommyjoking (****)

Date 11-17-2007 07:26

Zcat

I never worried much bout it personally..I used stainless brushes that were set aside just for this...if I felt they were dirty I would run them on a piece of 304 or 308 scrap to "clean them". On a thick xray joint (I never encountered one using carbon to SS), where a lot of cleaning in the groove was necessary, I guess I could see some measure of concern about it...but then there should be a specified cleaning procedure on a job like that as well.

My .$02
Tommy

By monsoon12 (**)

Date 11-17-2007 13:37

I welded a ss 1/2 plate at 2' to a wide flange beam.It was a t joint so i first cleaned the wide flange beam area.Then cleaned the plate before ever touching the 2 together.Then all i had to really clean was the weld it self.It saved me alot of time in cleaning an only had to use one wire brush.It was a fun project an hope to see more of them.I also got alot of great imformation from this site when researching it.Enjoy.