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Up Topic Welding Industry / Technical Discussions / Shielding Gas
- - By bosruten (*) Date 11-10-2007 16:14 Edited 11-16-2007 01:44
How does one qualify a shielding gas range for procedure to ASME sec. IX? i.e. 25cfph gives me a range of....?
Parent - - By 803056 (*****) Date 11-10-2007 21:56
ASME doesn't limit flow rate.

Al
Parent - - By bosruten (*) Date 11-14-2007 17:17
Thanks Al, I keep looking at QW 288.3(d) using a mixed gas and calculate 25%+/- of the lower to get the range but what if I'm using a unmixed gas....I'm confused. Do I just pick #'s out of the air for the range?
Parent - - By js55 (*****) Date 11-14-2007 18:03
Are we talking gas content or flow rate? I'm confused.
Parent - - By bosruten (*) Date 11-15-2007 00:56
A range specified in a WPS for flow rate, sorry for the confusion.
Parent - By js55 (*****) Date 11-15-2007 14:27
You wanna set your flow to give you enough coverage, but not too much to be either inefficient or aspirate atmosphere in behind the gas flow. 20cfh to 50cfh for GMAW or FCAW is common, 15cfh to 30cfh for GTAW is common. If your running gas lenses for GTAW you can get away with a little more but make sure you have a reason to.
Parent - - By 803056 (*****) Date 11-15-2007 16:23
Are you looking for recommendations of the flow rates to include or are you satisfied you have what you need?

I'm assuming you are not changing the gas or going from a single gas to a mixed gas.

Best regards - Al
Parent - - By jon20013 (*****) Date 11-15-2007 16:41
I think js55 hit it on the button.  There are some variables for some processes... if you are the engineer you ought to know where your range should be (ASME IX gives some percentages), if you're the craftsperson follow the WPS.  There's also an AWS Document (can't remember the number) that gives wonderful guidance for shielding gas usage.  It's an A.5 Document and you can find it in the AWS catalogue.
Parent - - By 803056 (*****) Date 11-15-2007 17:00
You may be thinking of A5.32, Specification for Welding Shielding Gases (the title is probably wrong, but close enough to find it). Two other documents would be the AWS Recommended Practice for GTAW and the manual available from the James F. Lincoln Arc Welding Foundation.

Best regards - Al
Parent - - By js55 (*****) Date 11-15-2007 17:32
jon is right there is a specific gas doc out there. I own the fricken thing and have read it, but it is buried in some boxes I have in storage and I can't remember its designation. Its A5 if I remember right.
It talks about Ar, He, CO2, N, H, etc., singles, bi mixes, tri mixes, quad mixes, short circuit, spray, globular, rotational transfers, carbons steels, low alloys, stainless steels, non ferrous alloys, GTAW, GMAW, FCAW, and PAW, heat transfer, penetration patterns, ionization potentials, mass, chemical activity, element transfer and oxidation, etc, and yes, even flow rates.
Its a great book.
Parent - - By jon20013 (*****) Date 11-15-2007 17:43
That's the one guy's!!!  Yeah, I've read it too... way too many moons back (shame on me!!!) but it struck me then and I remember it even now, of being a document of extraordinary value for the engineer... good stuff, the layperson never really stops to think just what a significant effect gas has on a process...
Parent - By bosruten (*) Date 11-16-2007 01:41
Thanks so much for the replies.
Up Topic Welding Industry / Technical Discussions / Shielding Gas

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