It's not often i can't sort out problems or find the reason, but I'm drawing a bit of a blank with this bar one realistic option, so this one is really for the experienced Miggers out there I would guess.
This particular job involves a lot of plug welds, that have to be totally porosity free for finishing reasons. Batch one went well (about 100 plug welds per batch) as planned totally porosity free welds and flawless when cleaned off. The welder is a brand new thermal arc bought more or less for this job for its spot timer facility. So to date, about 2 hours tops weld time on the plant using a brand new bottle of argoshield universal at 10 lpm. Second batch I started to get some issues (see images) with flaws in the weld, when cleaned off low and behold some form or porosity issue going on. I went through the whole process of checks as you do to no real avail. The result was re-working a lot of the parts very frustrating and time consuming.
The 3rd batch I'm working on now started off ok for the first 4 or 5 plugs then back to square one with this porosity issue. Sooooooo change all consumables in the torch for good measure. Played with pre flow uhhh no different, play with post flow... uhhh no different, upped the gas flow, downed the gas flow. Meddle with everything i can find...nothing makes any difference. Change the wire for good measure to prove a point, no different again...The only thing i have not (can not) changed is the gas!
Some welds come out ok others don't its very haphazard. 1 good then 3 bad.... the one thing is i can hear its not welding properly and it very much sounds a bit like when we forget to turn the gas on and go weld (we all know what that sounds like) but its not the typical zillion hole porosity i'm seeing.
I think its a fundamental issue going on here and i think its a problem with the gas, but not ever having a duff bottle before its out of my remit of experience. No settings have changed between the first batch and the problem occurring. The only other thing i can think of is the gas eddying and causing a problem, (see last pic) but batch one was flawless. This is mig welding so how hard can it exactly be? If you get my drift.
I'm convinced its duff gas... thoughts from the pros please.
This is the offending image, you may have to d/load this image a zoom it a bit
You can see the problem in the plug and the result when its milled off.
Close up
A good weld
pre welding pic
This particular job involves a lot of plug welds, that have to be totally porosity free for finishing reasons. Batch one went well (about 100 plug welds per batch) as planned totally porosity free welds and flawless when cleaned off. The welder is a brand new thermal arc bought more or less for this job for its spot timer facility. So to date, about 2 hours tops weld time on the plant using a brand new bottle of argoshield universal at 10 lpm. Second batch I started to get some issues (see images) with flaws in the weld, when cleaned off low and behold some form or porosity issue going on. I went through the whole process of checks as you do to no real avail. The result was re-working a lot of the parts very frustrating and time consuming.
The 3rd batch I'm working on now started off ok for the first 4 or 5 plugs then back to square one with this porosity issue. Sooooooo change all consumables in the torch for good measure. Played with pre flow uhhh no different, play with post flow... uhhh no different, upped the gas flow, downed the gas flow. Meddle with everything i can find...nothing makes any difference. Change the wire for good measure to prove a point, no different again...The only thing i have not (can not) changed is the gas!
Some welds come out ok others don't its very haphazard. 1 good then 3 bad.... the one thing is i can hear its not welding properly and it very much sounds a bit like when we forget to turn the gas on and go weld (we all know what that sounds like) but its not the typical zillion hole porosity i'm seeing.
I think its a fundamental issue going on here and i think its a problem with the gas, but not ever having a duff bottle before its out of my remit of experience. No settings have changed between the first batch and the problem occurring. The only other thing i can think of is the gas eddying and causing a problem, (see last pic) but batch one was flawless. This is mig welding so how hard can it exactly be? If you get my drift.
I'm convinced its duff gas... thoughts from the pros please.
This is the offending image, you may have to d/load this image a zoom it a bit
You can see the problem in the plug and the result when its milled off.
Close up
A good weld
pre welding pic