MIG 3G weld

Tue, 31 Aug 2021 15:35:37 GMT

go to see Welding Machine for MIG 3G weld

I'm currently taking MIG welding this quarter at my college and my last welding grades are for bend test in 3G. I thought I would post a few pictures of one piece I welded last night in class. I use 3 passes to fill the groove up. I'm having a difficult time getting full penetration on the start and ends of my root pass. Any tips? I've been trying to get my cover pass nice and uniform but it seems I'm always thinking I can do better. Maybe I'm too much of a perfectionist. Anyhow, I don't mind criticism at all. Attached ImagesLincoln Ranger 8
Replyooks good, Little undercut in a few spots unless it just the way the pic looks, Id go a little further on either side (not much im talking millimeters)  Id also go a little tighter. Feels like its taking forever but its well worth it if it means a ticket. Ive got my TSSA GMAW 3G as well.As far as the begining and ending of the root, make your tacks have a nice keyhole, then start the weld on the tack and work it in slowly, should fill in just fine.25 years of age.Been welding since Feb 23rd 2009.LU1007 Millwright (A1)
Replyo you have pics of the back side of the root? Many plate tests have a backing strip to help run in to the plate hot. Increase your heat and travel speed.UA Local 598
Reply:^ Really my test was open root no backing.25 years of age.Been welding since Feb 23rd 2009.LU1007 Millwright (A1)
Reply:We used run off tabs for starts and stops. What thickness is that plate? The reason I ask is simple, everybody claims that preheat is unnecessary with 3/8 or less thickness. But what can it hurt?  Your toes are washed in nicely, but make sure you are holding the puddle long enough to bring it up  above flush level. Overall it's looking good, but you said it yourself, you can do better. Keep that attitude, and you will do well. City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:I don't see ANY Penetration at the Start or Stop of your weld... You WON'T pass a Root Bend doing that...Glad to help you, but like the others have said, more information is required.I will cover the parameters of the GMAW 3G weld "Up here"3/8" x 6" coupons with 30° Bevels... About 1/16" Land, and 1/8" - 5/32" Gap...Open Root, NO Backing Plate.16.5 Volts, 175 IPM,(more or less) with 0.035" ER70S-6 Root Pass is Downhand with a Start/Stop about 1-1/2" from the start of the weld. (This coupon is for the Root Bend)Fill is Uphand.Cap is Uphand.No undercut is allowed.No Weld Reinforcement over the thickness of a Dime is allowed.Weld ripples are to be TIGHT, and pretty much "Flat" side to side.Half of the coupon is a Root Bend, other half is a Face Bend.Any flaws that cannot be covered by a 1/8" Electrode (Not including flux) means failure.While I appreciate the straightness of your edges, and the relative uniformity of the deposits, your coupons would NOT pass visual inspection "Up Here", much less a bend test.I would suggest a much faster travel speed, and smaller increments upwards on each pass across center...Last edited by Black Wolf; 08-11-2010 at 12:16 AM.Later,Jason
Reply:You should turn up and go faster and possibly start an inch from the end and run in to the edge on the bevel. There really is no reason not to have penetration at the end of your run when everything is hot.UA Local 598
Reply:Its 3/8" x 6" coupons with a 60 degree bevel, 3/32" landing and 3/32" open root gap. I had the welder set at 18.5 volts and about 250 IPM using .035 wire. Thank you all for the tips. I just need more practice to work out all my bugs.Lincoln Ranger 8
Reply:when I did my test for that I was able to use start and run off tabs in order to get proper penetration through the entire plate.
Reply:If your not using coupons with run off/on tabs (no backing plate), the outter edges of the plate will likely be trimmed and discarded before any strips are cut for bending.Your consistancy on your cap looks solid. Just tighten it up a tad.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720