----- Original Message -----
Sent: 3/3/2010 12:19:01 AM
Subject: Re: [PSUBS-MAILIST] MIG vs Arc
Hi All,
I am not a proffessional welder and have had much good advice over the years. Most of it it would support Dan's statement. I have been coached by a professional steam fitter with 25 plus years of experiance. His recommendations almost exactly follow Dan's and I cannot find fault in any of them. I have done test coupons and the results are amasing!!!
While my welds will never look as good as Dan's they are sound and follow sound basic welding principles.
Mig welding is fine, however there is a reason that it is not allowed itn structural situatioins!!! It is very unpredictible and sensitive to operator inputs.
My two cents!!
Best Regards,
Jim K
.
Scott,
I strongly disagree with Mr. Granato . It has been my experience on numerous occaisions to see weld test coupons done with MIG break . On one project alone I saw fifty welders have at least one out of four coupons fail ( as in snap in half ). Like I mentioned in a previous email my experiences are supported in the professional literature. There are so many varibles that will affect the outcome the only way to be sure is to do your own testing. That is what industry does. If Mr. Granato is talking about sheet metal then he is correct , it won't make a difference. In heavier thicknesses it most definately does. I have thrity years of welding experience and an investment in welding equipment worth tens of thousands of dollars. I have dedicated MIG welder but the only wire feed type process I will use to build a pressure vessel is Dual Shield Flux Core. MIG welding is fine for body work or building a motorcycle but not a submarine.! I would recommend to you to fabricate a guided bend test jig , weld up some test coupons using 516Gr70 and bend in a side bend mode. ( not a root or face mode) .
Dan Lance
----- Original Message -----
Sent: 3/2/2010 10:01:06 AM
Subject: [PSUBS-MAILIST] MIG vs Arc
I have been doing alot of reserach about MIG vs Arc. I contacted Miller here is their response:
Scott,
If you have the same filler metal tensile strength and set the machines to have the same heat input the end result should be the same. With the GMAW process you can use different shielding gases to give different penetration profiles but in the end with both processes you should be able to get the same results.
John Granato
Welding Engineer, Integrated Mig Systems
Miller Electric Mfg. Co. An ITW Company
1635 West Spencer St.
P.O. Box 1079
Appleton, WI 54912-1079
I am going to do a few pressure stress tests of my own, because of the wide array of answers I am getting, just to be sure.
Thanks,
Scott Waters
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