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I'm having a problem with craters in sub-arc welds (see attached picture). In several 30+foot welds I have these VT defects all the way through that are just giving me nightmares. UT testing comes out clean, so it is just a visual problem. What could be causing these?I was thinking it might be from moisture in the metal, moisture in the flux or just the type of flux in general. I am currently using ESAB OK Flux 10.72 with a grain size of 0.315-2.0mm.Anyone have any ideas??Thanks, Attached Images
Reply:I run into this sometimes when I either don't dump enough flux, or not adding new flux and just running the already used flux. I dont know about your procedures but flux should be heated just like 7018 before use. I know its subarc, but dont be afraid to hit it real quick with a grinder!
Reply:There is enough flux that's for sure (up to the tip at 1"), and we do preheat all of our flux to 300 degrees. We do recycle our used flux on a regular basis, but only for about 2 seams when our hopper gets low, then we add preheated new. It's very intermittent. We can run 30 seams with a half dozen spots in all, and then 4 seams that look like this all the way around.
Reply:There are some lincoln brochures online that show pictures and troubleshoot. Available in PDF files. I am guessing.... Too thick a layer of flux? I am wondering if the flux is preventing outgassing.wrong way ..maybe to little flux.. I found the Lincoln guide for you. Years ago this booklet made me look like I was soooooo smart. Ha Ha Other guys too lazy to read.http://www.lincolnelectric.com/asset...a-100/c550.pdfLast edited by lotechman; 08-23-2014 at 01:07 AM.Reason: lit reference |
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