High strength Steel GMAW difficulties

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Hi experts,we are doing some experiments on high hardness steel plates of 5/8" thickness using a double bevel but joint, with fully automated GMA, but as you can see in these pictures, getting a bad weld bead.the parameters that we used are 26 Volts, 235 Amps, 365 ipm for wire feed speed, 16.5 ipm travel speed. the contact tip to work piece distance was ~1 inch.could you please advice me how to adjust the parameters so we have better runs. at first we tried these parameters on low carbon steel and had decent runs.Thanks
Reply:I would say start by lowering your contact tip to work distance. What is your gas flow rate? Preflow/Postflow setting? What type of shielding gas? --Gol'
Reply:I agree with Go1lum. A bit closer. Also, what prep on the seam to be welded? And, what grade material; does it need some preheating? 5/8" is pretty thick for a non-submerged mig weld done at high speed/ deposition rates.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Originally Posted by Go1lumI would say start by lowering your contact tip to work distance. What is your gas flow rate? Preflow/Postflow setting? What type of shielding gas?
Reply:Is this on a robot, or an other piece of mechanized equipment. I would turn your flow rate down. More than likely to high. That can cause problems too, it actually creates turbulance and can suck non inert air into the weld pool. Especially with that much contact tip to work distance. Also ^ what he said, preheating is hardly ever a bad idea. --Gol'
Reply:Originally Posted by RojodiabloI agree with Go1lum. A bit closer. Also, what prep on the seam to be welded? And, what grade material; does it need some preheating? 5/8" is pretty thick for a non-submerged mig weld done at high speed/ deposition rates.
Reply:Originally Posted by Go1lumIs this on a robot, or an other piece of mechanized equipment. I would turn your flow rate down. More than likely to high. That can cause problems too, it actually creates turbulance and can suck non inert air into the weld pool. Especially with that much contact tip to work distance. Also ^ what he said, preheating is hardly ever a bad idea.
Reply:I would say get it down to 1/4"-1/2" range. Why so far away? This is likely causing you too loose shielding. --Gol'
Reply:Originally Posted by Go1lumI would say get it down to 1/4"-1/2" range. Why so far away? This is likely causing you too loose shielding.
Reply:To get into proper spray 26 volts is a bit low...  I would up it to 27 - 28 and stickout maybe 3/4 but no closer.  This is .045 wire?? Maybe even a higher argon mix to get a better spray.  The bead looks awfully narrow.  Your bevel prep is 30 degrees each side for an included angle of at least 60 degrees?  Your cap should be around 3/4 inch wide if you are using 60 degrees.  That clamp foot is about one inch wide which makes me become suspicious that the prep is incorrect.
Reply:Originally Posted by lotechmanTo get into proper spray 26 volts is a bit low...  I would up it to 27 - 28 and stickout maybe 3/4 but no closer.  This is .045 wire?? Maybe even a higher argon mix to get a better spray.  The bead looks awfully narrow.  Your bevel prep is 30 degrees each side for an included angle of at least 60 degrees?  Your cap should be around 3/4 inch wide if you are using 60 degrees.  That clamp foot is about one inch wide which makes me become suspicious that the prep is incorrect.
Reply:You should really be using .045" wire at that amperage range. .035 doesn't really support spray transfer. Are you trying to achieve spray transfer?Try the flow rate at about 20CFH --Gol'
Reply:Originally Posted by Go1lumYou should really be using .045" wire at that amperage range. .035 doesn't really support spray transfer. Are you trying to achieve spray transfer?Try the flow rate at about 20CFH
Reply:Spray transfer is a Mig welding wire transfer mode. It usually takes place above 200 amps. The wire comes down makes contact with the base metal. Then it burns back and small metal dropplets (smaller than the wire diameter) are transferred across the arc. It produces nice smooth spatter free beads. It will be a nice quiet arc. Not the typical short circut transfer that most mig welding is done with. (that bacon frying in the pan sound) Unlike SCT the arc is on all of the time except on arc initation. In SCT the wire dead shorts typically 20-200 times per second, the resistance builds up, the wire necks down and breaks off and the process repeats. ( thats what gives the crackling sound) Spray transfer is done typically on thicker material with .045" wire minimum, and the shielding gas must also support spray arc. typical 75/25 doesn't contain enough argon to support it. typicaly about 85-90% argon is needed to support spray transfer. other gases such as 98/2 argon oxygen are great for spray transfer.  I would also try to get a 98/2 Ar/Ox gas mix, I have had great success spraying with that. --Gol'
Reply:Originally Posted by Go1lumSpray transfer is a Mig welding wire transfer mode. It usually takes place above 200 amps. The wire comes down makes contact with the base metal. Then it burns back and small metal dropplets (smaller than the wire diameter) are transferred across the arc. It produces nice smooth spatter free beads. It will be a nice quiet arc. Not the typical short circut transfer that most mig welding is done with. (that bacon frying in the pan sound) Unlike SCT the arc is on all of the time except on arc initation. In SCT the wire dead shorts typically 20-200 times per second, the resistance builds up, the wire necks down and breaks off and the process repeats. ( thats what gives the crackling sound) Spray transfer is done typically on thicker material with .045" wire minimum, and the shielding gas must also support spray arc. typical 75/25 doesn't contain enough argon to support it. typicaly about 85-90% argon is needed to support spray transfer. other gases such as 98/2 argon oxygen are great for spray transfer.  I would also try to get a 98/2 Ar/Ox gas mix, I have had great success spraying with that.
Reply:In the shop I work in part time we are welding 1/2 inch plate to one inch and 350 ipm is approx speed for .045.   Some guys are running 400 ipm if they are welding down in a flat butt joint.  One needs a large power source to do the job as Go1lum indicted.  As a general rule you are better to run more passes rather than slow down and let the puddle build up.  If you are running an open root.. of course the heat will have to be less on the first pass.... maybe done manually.  Make sure you measure the plate bevel angle to be consistent.Terminology on contact tip to work and contact tip to end of wire sometimes confuses.  You need about 3/4 tip to work at least for the wire to preheat before arc and allow contact tip to survive.  This is not nozzle distance.
Reply:Originally Posted by Go1lumYou should really be using .045" wire at that amperage range. .035 doesn't really support spray transfer. Are you trying to achieve spray transfer?Try the flow rate at about 20CFH
Reply:0.035 steel wire will spray.  With the correct voltage and WFS and shielding gas, of course.0.030 steel wire with C10 should get into spray mode at around 160 amps.0.035 steel wire with C10 should get into spray mode at around 180 amps.0.045 steel wire with C10 should get into spray mode at around 220 amps.Besides, if you got 'good' spray transfer with 0.035 wire on the plain steel test pieces, then you got spray transfer.I think you have a few parameters not lined up quite right.  The CTWD of 1 inch seems a bit too much (5/8 to 3/4 inch CTWD is more what is recommended).At 'higher' amp settings, remember that the gas flow is shielding the weld -and- cooling the torch.  Spray transfer with C10, Lincoln says use a gas flow rate of about 40 CFH +/- 5 CFH.http://content.lincolnelectric.com/p...ture/c4200.pdf   Page69, GMAW spray on flat butt joint of steel, 0.035 wire with C10 at 40 CFH, 500-600 ipm WFS @ 29-30 V gives approximately 230-275 amps.  Travel speed called out as 10-15 ipm.  CTWD 5/8 to 3/4 inch.re: Joint prep  Unless you are dancing along with a GTAW root pass, I think you have have the wrong dimensions on your groove prep.  A 1/8 inch gap with a 1/8 inch land and blasting 230+ amps at it in GMAW spray mode?    Same document, same page, joint prep call out is a tight butt with a 60 degree bevel of approximately HALF the workpiece thickness, make the top-side pass, and THEN go back and gouge or otherwise bevel-prep the back side and finish welding there.  You had this skinny land with a gap and then you blasted a good bunch o' amps at air in spray mode.All of the previous really doesn't care if you are welding mild steel, or medium-carbon steel.  Once you go to a 'hard' plate though, you then have to additionally deal with the necessary pre-heat and the weld and weld filler chemistry.Pre-heat, redo the prep geometry, and run the 'suggested' parameters.Oh, and if you really are using HSLA steel, then maybe pick a different filler instead of ER70S-6.  More like an ER80, ER90, or ER100 type of filler, depending on the exact material and weld properties you are trying to achieve.Lincoln LA-100 filler, ER100S-G, 0.035 with C10 in spray mode, 23V at 195 amps at 375 ipm WFS to 30V at 275 amps at 600 ipm WFS.  Current product catalog C110, Page 120.  http://content.lincolnelectric.com/p...ature/c110.pdfLast edited by MoonRise; 11-22-2010 at 10:25 AM.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by BCRDI beg to differ on this point (although everything else is agreeable). I use .035 wire in spray transfer often enough. I'm not saying this is the best wire size for his application, just that .035 will work. Oh, and I use 90 / 10 as well.Jason
Reply:Damn.... ask a good question, get 20 GREAT answers!! Thank you very much guys. There was more great info shared here in 1 day than in 2 months of shop work.Threads like this are what made this site!!!!And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:OK guys, ready for some updates?the only changes that we made were 1-gas type(!!!) [from Ar-CO2(90-10) to Ar-O2(98-2)] and 2- as you all said, CTWD from 1" to 5/8-3/4"and hopefully we had decent runs on carbon steel, even with 24 or 25 Volts (as you can see).we will try the main plate tomorrow with the aforementioned parameters to see how it works.one more thing, those small circular slags(or something like that) seems to be silicon that comes up to the surface, right?stay tuned guys  Attached Images
Reply:Wow- major improvement!!! Yes, the rain drops are just silicons. Clean it up, and prime it or send it out for galvanizing, you are looking good.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:The whole idea of extra silicon in the wire alloy is to capture oxygen and form those silicon oxide islands.  Make sure you remove them before painting.  If galvanizing those islands will resist acid action and prevent the zinc from sticking.  I get paranoid about them if I am faced with some serious inspection and remove them before putting down another pass.
Reply:Just curious, did you do this weld in one pass and does your machine whip(weave) or do you just centre it in the middle?Miller Auto Invision 456 + S-62 wire feederC6240B1 Gap bed lathe16 ft3 air compressor16 speed pedestal drillHafco BS-912 Bandsaw
Reply:Looks better.However, your run-off onto the run-off tab stopped short.     You have an ending crater on the workpiece.And yes, those little 'glassy' droplets are silicon islands cause by the (on purpose) silicon in the filler wire doing its job as a deoxider.  Remove them before finishing (paint or whatever).Also, as I mentioned before, if this really is a HSLA steel or other 'strong' material then you probably should be using a different filler AND doing preheat on the workpieces.  Along with possible post-weld heat-treatment.  The best laid schemes ... Gang oft agley ...