Strengths of underwater welds

[enginerding]

This is probably a stupid question, but I can't seem to find the answer anywhere in these forums or elsewhere on the internet...

Is there any difference in the strength of welding electrodes for underwater welding? Can I specify an E70XX electrode for underwater welding, or does that become a strength that is not usually specified under water? I don't want to call out something that is not usually done.

 

[kslee1000]

See if the link below helps or not.

http://www.welding-advisers.com/Underwater-welding.html

 

[enginerding]

No. I found this website already, but it doesn't talk about typical strengths of electrodes.

 

[GRoberts]

I haven't been involved in underwater welding, so instead of hazarding a guess to your answer, I would recommend picking up a copy of AWS D3.6. If it is like the other AWS specifications, it should have a design section. Unlike other AWS specification, I do know that underwater welding has different classes of welds based on the expected quality. That could affect your design allowables as much or more than the strenght of the filler metal used.

 

[kslee1000]

Roberts is correct on AWS D3.6.
Here are two articles that have scant touch on welding rods. Both are from the Navy, maybe you want to visit its website to find and download relavent manuals/specs.

 

[kslee1000]

Here is the 2nd.

 

[SJones]

There are 4 classes of welds designated in AWS D3.6 with type A being considered equivalent to a weld made in air. It has been possible to achieve type A welds underwater but it is by no means routine. Of course, electrodes can be specified on a normal strength classification basis but it will not guarantee that the specified strength is achieved underwater. For structural load bearing welds, it generally ends up in a fitness for service analysis exercise since porosity, inclusions, and hydrogen serve to degrade ductility, toughness and, possibly, strength.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[BAretired]

Great information, kslee.

BA

 

[kslee1000]

Thanks BA.

I think enginerding has yet to find out what is the weld strength he can rely upon for his design. This topic been very educational to me.