GMAW pushing versus draging witch gets better penetration?

Date 06-15-2007 15:25

Kix,
My thought has always been that unless you have a specific problem manifest in rejections or welding problems, then it is best not to try and impose particular techniques on welders. Research data will do little to convince hard heads. Welding is more of an art than a science. And there are as many ways to achieve good welds, technique wise, as there are welders. If the welds are doing what you want them to do, personnalyI wouldn't make an issue of it.
If the welds are failing use that to convince him.

By Kix

Date 06-15-2007 15:47

Trust me i'm not one to impose on ones technique and i tell anyone i train to do what they can do best to put in a good sound weld. This welder has had issues and i was told to work with him. He says he was taught that you get better penn when you push and i was simply correcting him and he doesn't want to hear it. Now about the the wire in the middle of the puddle issue. I welded with his machine and everytime you made a swoop and came to the leading edge of the puddle it would pop and spudder witch tells me he is to cold. However when you just ran the wire back in the middle of the puddle it ran smoothly, but what does that tell ya? Again, if you have to run it back there to get it to run smooth your too cold and when you run on top of the puddle you reduce your pen. Now these are critical lives at stake welds being made here so i'd appreciate some help with a hard head when lives are at stake.

Thanks, Kix

By js55

Date 06-15-2007 16:02

Kix,
Duly noted.
Per ASM Volume 6 1993, Chapter-Gas Metal Arc Welding:
"For all positions, a trailing travel angle that ranges from 5deg to 15deg from perpendicualr provides the weld with maximum penetration and a narrow, convex surface configuration. It also provides for maximum shielding of the molten weld pool."

By js55

Date 06-15-2007 16:07

The AWS Welding Handbook Volume 2, 8th Edition Chapter 4 says essentialy the same thing. By the way, DB Holliday of Westinghouse wrote the ASM chapter and was Chairman of the AWS Handbook chapter.

By Kix

Date 06-15-2007 17:05

Can you see any of that text on the web so i can print it and some macro etching pictures would be great too? I don't have any of those books so i'm kind of in a bind. Thanks for that info though!!

By js55

Date 06-15-2007 17:19

Kix,
Neither of those, to my knowledge will be found on the web. However, you may also try Lincolns and Millers web sites. They both have 'Manuals' on GMAW. Those docs ARE on the web and are free. As for macros, I don't know that you will find those on the web anywhere. There are some AWS Welding Journal Research Supplements containing macros I'm sure, that are web accessible, but how to find a particular one I dont' know.
Sometimes they pop up when you google particular subjects.
Try googling GMAW itself and see what you come up with. Theideas your looking for are common. And there are plenty of instructional sites out there.

By Shane Feder (****)

Date 06-15-2007 20:09

Kix,
Try this posting, it may help

http://www.aws.org/cgi-bin/mwf/topic_show.pl?pid=36400;hl=#pid36400

Regards,
Shane

By Kix

Date 06-18-2007 12:56

I had to bust out the big guns and have this guy do some macros to show him. They came out just the way i predicted and he was really surprised. Now he respects my skill and knowledge a bit more and everyone is on the same page.
I could of sworn i posted this allready, but i think i might have done it in the wrong topic.oops It all started when i told him his machine was junk and he thought it was welding fine. I welded with his Linde machine and found that there was a huge gap inbetween the hi and lo settings. His lo setting all the way pegged was just not enough and his bottomed out setting on hi was to hot. So i had maintenance come look at it and i guess they told him it was fine and did not bring him a new machine. I went back over there and welded with it some more cause the welder said it was welding better. This is where the hole running back in the puddle came in to play. I knew it was to cold because everytime i would bring the wire close to the leading edge of the puddle where you get the most penn it would pop and studder, but when you ran the wire back in the puddle it would run fine. I told him this isn't gonna fly and i promise i will get him a machine that runs just as nice and i'll help you set it up. So maintenance came back and told me that the machine does overlap in the high and lo settings and that i don't know what i'm talking about. He said it goes to 27 volts pegged out on lo and 26 volts bottomed out on high. Well, right then flags went up and i told him there's no way in you know where that that thing is running at 27 volts pegged out on lo and it was more like 16.5V or 17V just from how it felt. So he went over to show me and guess how he showed me. He pulled the trigger on the gun and let the wire run and read the volt meter and said see there ya go 27 volts on lo and then he swapped it over to hi and did the same thing. So i said ok now lets do it the right way and i told the welder to grab his hood and weld on some scrap and wow what do ya know 16 volts. I missed it by a half a volt. I know you guys get the picture of the rest of the story so i'll shut up. ;-)
Thank you all for the quick replies and knowledge!!! I read that topic that shane posted and it just amazes me about the hole push/drag topic and what people are taught and what they're told.