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304 to 316 question

Posted: Sun Feb 03, 2013 3:32 pm
by Otto Nobedder
I don't often ask a question here, as I'm not often called to do something I'm not already familiar with (a shame, really, because I like trying new things), so I just absorb new knowledge from others' questions and answers.

However, I'm replacing a structural component, originally 304, with 316. The backstory is, there were many cracks in the original part, every one originating under a gusset that was MIG welded both sides and not closed at one end. The client's engineers' working theory is that the road de-icing chemicals other than salt, commonly use in northern states and Canada when it's too cold for salt to be effective, or during salt shortages, gets trapped in the space beneath the gussets, between the MIG fillets. I've seen evidence that seems to support this.

As an experiment, I'm repacing the damage with 316, and will be welding it to a stub-out of undamaged 304 that was not under the gussets (there were corner cut-outs).

The weld must be vacuum-tight, and will be structural in a load-bearing member. Vacuum-tight is not an issue, but:

Should I make the weld with 308, or 316 rod? Or will it matter from the standpoint of strength and ductility?

Steve S

Re: 304 to 316 question

Posted: Sun Feb 03, 2013 3:42 pm
by Otto Nobedder
Here's the structure I'm repairing.
GEDC0516.JPG
GEDC0516.JPG (196.2 KiB) Viewed 892 times
And here's the component I'm replacing.
GEDC0555.JPG
GEDC0555.JPG (198.64 KiB) Viewed 892 times

Re: 304 to 316 question

Posted: Sun Feb 03, 2013 6:33 pm
by weldin mike 27
Hey mate,

Heres a link, i hope its what you're after. I find that Lincoln offer a no fuss system of answering questions.

http://www.lincolnelectric.com/en-us/su ... etail.aspx

Mick

Re: 304 to 316 question

Posted: Sun Feb 03, 2013 7:01 pm
by Otto Nobedder
Thanks, Mick,

It's a piece of the puzzle... It suggests 309 is out because of the absense of Molybdenum, which is a component of 316. I'll have to check 308 for content.

Steve S

Re: 304 to 316 question

Posted: Mon Feb 04, 2013 1:29 am
by weldin mike 27
Hey,

dang nearly got it. Try seaching that area of the lincoln website, i think youll'll find what you want.

Mick

Re: 304 to 316 question

Posted: Mon Feb 04, 2013 4:25 am
by weldin mike 27
Hey,

Have sent you an email on this subject.

Mick

Re: 304 to 316 question

Posted: Mon Feb 04, 2013 8:14 am
by Alexa
OttoNobedder.

If you are welding 316, then 316 filler is recommended.
Respect the upper limits on heat input and interpass temperature.

Alexa

Re: 304 to 316 question

Posted: Mon Feb 04, 2013 8:37 pm
by Otto Nobedder
Thanks, Mick,

Got the e-mail. Much appreciated.

Steve S

Re: 304 to 316 question

Posted: Mon Feb 04, 2013 9:12 pm
by weldin mike 27
No worries mate. May need to print the table out to avoid a sore neck... (Sorry everyone else, inside joke . )

Mick