Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / General Welding Discussion / x ray welding
- - By scooby (*) Date 04-29-2009 03:00
Hi guys I have a question and was looking to pick your brains  when you are welding x ray what kind of  routine do you go through as for prep for example grinding  cleaning. i work in a  small vessel shop we dont always get of x ray work but when we do it comes in bunches.  some times im having a issue with porosity seem i get it only on spot x ray  is it that my gun angle is off maybe to much wire or am i not geting the material clean  to much gas maybe we only do mig and tig at my shop . heres my setting i use  machine is miller deltaweld i run abouot 3 ipm on wire with 19.6 on volts at about 160 amps gas between 30-35 was just curious im a good welder never have any leaks on my vessels just trying to improve myself any information and tips will be greatly appreciated thanks scott
Parent - - By Metarinka (****) Date 04-29-2009 03:27
what type of material and gas are you running

also how does the porosity look is it in a line for a section of the weld or just in one spot?, near stops starts?

guessing that you are using a common wire size it appears that you are running low, 19.6 v and 160 amps is generally short circuit on all but the thinnest wires.  Also if you're welding indoors 30-35 CFH of gas seems a bit excessive, shouldn't need to go much over 20-25 if even that.

it's hard to say without looking at the x-rays and welds myself.

If it's coming in clusters it might be due to an issue like cleanliness of the pipe, perhaps even oil on the wire (although that's usually rare in MIG)  IF it's in a line or all throughout the welds that indicates something is going on with the welding process like bad or contaminated gas, leaky hose etc.  Finally if it's around starts or stops (which are going to be hard to remember on piping) it might be from bad technique or maybe your MIG machine doesn't prepurge long enough? OR you aren't cutting off your stubbies. Million different things

Those are a couple guesses I would give, again without looking at the pipe myself. Also for future reference I was scratching my head when you said your wire feed was at 3 IPM I'm guessing the machine has a face plate that goes 0-10? because generally wire feed speed is in the range of several hunder IPM  so for future you can time yourself letting out wire for 10 seconds and multiply that by 6 to get your real WFS.  It's what I did when I used to write GMAW procedures.
Parent - - By scooby (*) Date 04-29-2009 21:41
metarinka
in response to your feed back  material is carbon steel anywhere from sch 40 to 160 and running 75-25 for gas the reason i keep it around 30 is because my area is right next to the door and they keep it open when the weather is nice sometimes gets a little breezy so i just move my curtian over. we use .035 wire  i always clip my wire prior to start and i run my wire at 300 ipm amps are around 160 and yea its short circut the porosity is very spotty and i can tel you for  fact that my machine dose not pre purge long and when i clean  the pipe i usually clean 1 inch in on the inside and atleast 2inches on the outside right down to shiny material i looked at the film today and  no porosity near my cover stop or start so i dont think thats a problem and all the porosity was in a straight line  im thinking my angle might be to steep and i need to come up on the pipe more . if i can get a pic i will.
scott
Parent - - By cmays (***) Date 04-30-2009 03:04
Are you welding in position or roll out? In roll out (1G) sometimes if you get the tip of the gun pointing too far across the top of the groove rather than closer to the center of the  pipe you will get porosity due to loss of gas coverage. Its really hard to explain w/o  showing you my self. Ive experienced this myself though dealing with the gun angle.
Parent - - By scooby (*) Date 04-30-2009 21:12
cmays in am welding in roll out(1G). (hey look at that i used a puncation mark) I did a cap to shell today and our tech took a couple of shots for me today. I came up on the pipe more towards the center of the pipe and and stayed that way for each pass and wouldnt ya know nothin clean as a whistle. I also did turn my gas down a little to 25. so tom I will have another one and i check back and let you now how i made out. Now as for you Mr. Kane I got on this site looking for help and you chime in because i Forgot a couple capitals and periods do me a favor and dont respond unless you got something for me to toy with or help me figure out a problem. Im not the smartest on the computer and sometimes i get caught in the moment and forget but im young and trying to learn and if you can't help then dont post. thanks again for the help
scott
Parent - - By cmays (***) Date 05-01-2009 00:23
Cool man basically you want your gun angle to allow gas to  cover on top and under your puddle. For example: Imagine your puddle is the  dash and the two  diagonal lines are gas coverage       <----
Hows that for use of puncuation?      
Parent - - By scooby (*) Date 05-01-2009 02:19
pretty sweet use of the puncation now heres another question. If i turn my gas up even more say to 35 it will spread out my coverage  area  im not gonna do this til i get a response. Now how does this apply to fluxcore  should i be thinking the same as mig. Thanks for your help cmays i really appreciate it.
Parent - - By cmays (***) Date 05-01-2009 03:16 Edited 05-01-2009 03:26
well if you get too much gas flow you can focus the column comming out of the nozzle this will prevent it from creating an umbrella around your puddle. As you move your nozzle back and forth you can loose coverage because your gas column is so focused. Clear as mud? With dual shield ( Im assuming you have a stringer pass already in ) stay up on top and keep the gun angle pointed slightly towards the center of the pipe. I like to walk the nozzle backwards sort of like walking the cup backwards with the gun angled down into the puddle. This keeps your arm from fallin off from fatigue before youre half way around. Youre not going to have loss of coverage because you have something under your puddle already (stringer pass). Good luck man.
CM
Parent - By scooby (*) Date 05-01-2009 21:43
hey cmays tried again today and was money 3 for 3 clean as a whistle.  All angle was to low. and Im not gonna screw with my gas setting gonna leave them between 25-30. Thanks again for taking the time to help i know i might not of explained everything perfectly or forgot a few things here or there but just giving input was enough to get the old memory thinking. Ill look ya up again if i have any questions. or need help with my grammer lol.
scott
Parent - By Joseph P. Kane (****) Date 04-30-2009 09:49
punctuation  --  capitals   ?????????
Up Topic Welding Industry / General Welding Discussion / x ray welding

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill