The 5356 is OK. the 75/25 should be OK but is expensive. Is the crack at a crater at the end of the weld? are You reversing direction at the end to fill the crater?
If the parts get anodised You need the 5356 for proper color match, there may be mechanical reasons for it's use also.
The helium in the gas mix increases heat input, You don't necessarily need it for 1/8 & 1/4 sections.
Do You have to meet any minimum strength requirements after welding? If so extra heat is the enemy.
Where to begin?
First off, 5356 is much stronger than 4043, but there's a trade-off. 5356 requires much higher current to make the same penetration as the 4043. If you are welding to a WPS which was qualified using 4043, it won't work with 5356. Also agree that the mixed gas is a waste of $$. Pure argon works very well with GMAW-AL. I'll bet you're also getting IP in the first inch of weld on cold parts. As far as the cracking goes, there are many potential culprits there, and we need a little more information to help you out with that. What is the joint geometry, voltage, WFS, gas flow, position, speed of travel? And I'll go ahead and ask if you are using preheat at all.
haha where to begin is right'
my terminology is not that great so bare with me, there preaty basic here at the plant we weld vert up and t-joint style welds along with over head,i totally agree on gas cost been trying to tell them that and some of the other guys in the shop use liquid arg but this inspec says we have to use the 75/25 mix in spay arc for max pen. not really sure what ip is, he has me set at around 25/30 volts, gas i think is set at 25 and wire travel i set based on the position im running,i try to set the wire speed and do as many of the same position welds as poss without getting to much heat pull and then change for another position.my job is to build the floor framing and wall framing,not sure if i can post pics here or not but i do have some.oh and no preheat. one thing i do try to do now is place a tac where my stopping point will be and run on top of it,helps alittle. now when he started testing us he had already chaged us to to 5356 wire mix gas and ran us on 3/8 plate 6 inch long and we past but part of the issue is were not running 6 inch plate secured on a table im on the floor under the frame trying to weld 2 and 3 inch welds and yes sometimes the start area looks like a 12 yr old did it so i end up cutting the weld out so i can make it better.this new process seems to have added about 2 or 3 hrs to my build time for some reason. on a side note with this process he has us on he gave us a welding reference guide to look at that says were using wrong wire-confusing...but again thanks for any help ill try any suggestions.
IP = incomplete penetration.
Example:5356 on 6061 plate, 100% argon, 25v, 260 ipm. This was run in the 2F position.
we should be starting a new trk this week and if i can ill get fresh pics for you.welds just look wrong,cold looking even at 27v area. gonna try some different settings and positions to, see what happens
Man! look at all that porosity also!!! ;)
Respectfully,
Henry
4043 0r 5356 wire is acceptable for the 6061 T6 material, I find the 4043 wire easier to run Myself. As to the strength difference, In my opinion, the HAZ is probably going to be the weakest link.
I agree with you Dave. It makes little difference from a strength stand point whether you use 5356 or 4043, the HAZ is the weak link. While the "as wrought" condition is 42 ksi, the "as welded" condition is acceptable if it meets 24 ksi tensile strength.
Many welding problems can be traced back to improper cleaning and welder technique.
Porosity - cleaning. Any oil, grease, finger prints, paint, moisture, etc. will result in porosity. Hydrogen loves to swim in the molten puddle, but the solubility decreases on the order of 1000/1 in the solid state, so it typically manifests itself as porosity in the weld.
Incomplete fusion - make sure you are in the spray mode and make sure you use a push technique rather than a pull technique (forehand versus backhand). Aluminum does tend to start cold and there will definately be fusion problems if the joint isn't wire brused with a stainless steel brush just before welding. Likewise always wire brush between passes when making multiple pass welds.
DO NOT PREHEAT the aluminum.
There's been numerous threads on this subject. Do a quick search using the keyword "Aluminum".
Best regards - Al
Agreed. 5356 is harder to run, and in my experience 4043 does just as well a job, unless you have to color match for anodize.
The porosity in the photo was a secondary consideration. Cleaning for this run was minimal, since my intent was to show the difference in penetration between 4043 and 5356 using the same machine settings. So I wasn't really surprised to see it there. :)
well i tell ya,not aloud to take pics so no help there,we spent an hr. welding 3/16 tube to 1/2 flat bar on one side. put in a vice and snapped it off with no penetration to one side or the other and that was set at 28 v and about 200 a. now i got a hair and jacked it to 34v and 240a and it broke right down the center of the weld, but its not a spray arc weld,when we told the inspec what setting we used he said nope to hot need to be within 24/26v and 220/240 wire,heck i could hardly tac it together. im wondering if its not the machine. will do some more playing tomm. thanks
Since you are welding aluminum with GMAW, spray mode transfer is the preferred mode of transfer. You can weld aluminum in all positions using spray transfer, so there is little reason to consider short circuiting transfer unless you are welding very thin sections.
The inspector is telling you to use low voltage while welding, the 200 amps is within reason assuming you are using 0.045 inch diameter electrode. Are you actually working with a written welding procedure and was it qualified by testing? The reason I ask is that the voltage sounds low for true spray transfer. If you don't have a WPS supported by a PQR, the inspector has little reason or justification to impose arbitrary welding parameters. You should have little difficulty welding at 28 volts and 200 amps if the aluminum is cleaned just prior to welding. 34 volts sounds very high. Then again, that begs the question; "Are your meters calibrated?"
Best regards - Al
34 volts & 240 amps and it's NOT a spray arc? That sounds WAY too high to be a short circut arc.
I have to agree with Al that there might be a calibration problem, or a poor connection someplace and You might not have the voltage at the arc that You read on the machine.
i agree with the both of you (Al/Dave) something is not right and its getting so old that its almost funny anymore,we have 2 machs.both have same feeders but the strange part is the meters both read about the same. now when i did the welds with the higher settings they were harder to break and broke down the center of weld and visual was more of a long arc i guess you call it, but i had to turn mach. down to weld some other stuff for someone and when i turned it back to the high setting it was much much hotter of a weld and not spray. so it could very well be out on calibration so now were playing by eye. now the inspector does work at a sister plant and is coming next wed.so i told him to be sure to bring a helmet and some patience cause its gonna be a long day. again i thank you guys for the responces and i do listen and what ever i pick up here i do try at work
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