"fused metal backing"

By cwipaulk Date 05-07-2012 23:45

We are having an issue at work with metal backing. D1.1 clearly states that the metal backing will be continuous (meaning welded together if needed)for the full length of the weld.
D1.6 states that when "fused metal backing is used", it will be for the entire length of the weld. The question is, what are they calling "fused metal backing"?
Some of us say it is the same as in D1.1 - welded together (CJP), but our supervisor says it can be butted together and not welded, even though it is a stainless CJP weld.
He says the "fused metal backing" refers to the backing being fused to the base metal during the welding process. It doesn't seem that D1.1 would have one requirement
for metal backing, and D1.6 another. The new Welding Manager also interprets it to mean that the backing bars can be butted together and not welded to each other.
Which is it?

By eekpod

Date 05-08-2012 11:07

Here is my intrepreatation of that requirement.
D1.6 5.6 Groove WEld Backing "when used, fused metal backing shall be full length of the welded joint........"
5.6.2 "Groove welds made with steel backing shall have the weld metal fused thouroughly with the backing and shall be welded in a manner that meets the quality requirements of this code."

Clearly 5.6.2 says the weld when deposited shall be fused to the backing bar.
5.6 says the backing shall be the full length and shall be fused to the weld joint. I intreprep this to say the joints of the backing shall be fused. Note this is different than CJP like in D1.1. So with S/S the individual pieces of backing can be fused/ welded together to make one continious bar but the joints don't HAVE to be CJP.

D1.1 requires the joints of the backing to be CJP from what I remember.

Just my opinion, others may be different.

FYI the commentary is worthless in D1.6

By cwipaulk Date 05-08-2012 11:43

Thank you sir for your reply. I am in agreement with you that the joints of the backing should be fused together.