Stainless steel to A615 rebar

[strguy11]

In the field, the contracter cut a headed stud off of a stainless steel embed plate due to a conflict with another bar. To remedy the situation, the contractor is proposing to weld a piece of rebar on the bottom of the plate to compensate for the missing stud. I have checked everything, and structurally it is ok, however, I was wondering if the dissimilar metals will pose a problem. The plate will be exposed to weather, however the face where the weld has occurred will be embedded in the concrete.

I have read that this type of welding can lead to corrosion, however if a galvanizing repair paint was used, would this be ok??

 

[Lion06]

although I am not sure about welding these two metals together, they shouldn't pose any problems in terms of galvanic corrosion.

 

[civilperson]

The welded joint will be embeded in concrete? Then OK for corrosion, check chemistry of weld stick for compatibility.

 

[JAE]

A615 is not normally used for welding. Use A706.

Or better yet you can buy what are called Deformed Bar Anchors - ASTM A108 AND A 496 (Fy = 70 KSI)

 

[JStephen]

Could he just weld a headed stud back on?

On the corrosion issue- you often see information that says attaching dissimilar metals can lead to corrosion, but seldon if ever see anything that says how much or how fast, or whether it will be a problem in your lifetime. Seems like I have read that galvanized items shouldn't be attached to stainless, so I would avoid the galvanizing repair paint- just use plain epoxy if anything.

Seems like some A615 isn't easily weldable- make sure they have that covered.

 

[PackerFan]

I would caution against welding stainless steel and a steel rebar together. These two metals are about as far apart on the galvanic series chart as you can get. Since the stainless steel is the cathode (protected end) the stainless steel plate will "rust" slower than normal and the steel will act as the anode (corroded end) and will "rust" much faster than normal. Brittle materials like a weld that have disimilar metal issues can also lead to problems with HASCC(Hydrogen Assisted Stress Corrosion Cracking). A cold galv coating will not prevent galvanic reactions. If you are confident that there will not be any moisture, then no problem. Just my two cents.

 

[Lion06]

Jstephen-
I have a pretty good paper on galvanic corrosion at the office. I will tell you the reference when I get in this morning.

 

[Lion06]

Jstephen-
I don't have an article name or reference on this article, but if you have an email I would be glad to email it to you. It is a very good article and has the galvanic series chart that Packerfan references.

Also, I mis-spoke earlier when I said the galvanic corrosion would not be an issue. I only looked at it one way, not both ways. Packerfan is correct, I would not weld these two together (for more than just the weldability aspects).