Thread: 6G Welding Test (what was I thinking)

Is it possible to sit down and do the welds?
Can you set up some RHS or timber blocks to rest your hands on?
Can you get on the floor to do the overhead portion, then stand on a stool to do the downhand section?
Can you wear a couple of pairs of gloves to do the really heavy welds? I sometimes wear a mig glove over my tig gloves when doing overly hot work. Interrun passes must be done after the weld cools below 230deg (AS1210) so you can get a fair bit of a weld done before it gets too hot to rest on with two gloves.
Definitely backpurge the weld as you'll get ugly growth on the inside of the pipe with the stainless.
Do you get to specify the weld prep and gap? I like a minimal root face for tigging pipe as I can control the peno better you may be different but it is something to think about. I like a bigger gap too but you need to be careful there as it is easy to get a concave weld face inside the pipe when doing that.

If you have the opportunity to practice these welds then do it, 6G can be a right bitch to get right as you have so many different positions you have to contort yourself into

Practice Practice Practice....

Sorry I can't offer anything for MMAW but I have only done 6G in Mig and Tig, and only regularly do it using tig at work and even then I'm not fully fixed at 45 deg. Hopefully you don't have to do a pipe to plate to simulate a flange then butt weld pipe too, that'd be a fun day spent welding!

Hi Ben78,

Is it possible to sit down and do the welds?
Yes, you can do anything that makes you comfortable. The inspector was a nice guy and must have seen my lack of experience and was giving me some good tips.

Can you set up some RHS or timber blocks to rest your hands on?
Im not sure about this one, i was using a thick glove on the pipe to rest my hands on.

Can you get on the floor to do the overhead portion, then stand on a stool to do the downhand section?

Yes you can use a stool.

Can you wear a couple of pairs of gloves to do the really heavy welds?

I use some tig Gloves and have some really thick gloves to rest on the pipe when it gets too hot.

"I sometimes wear a mig glove over my tig gloves when doing overly hot work. Interrun passes must be done after the weld cools below 230deg (AS1210) so you can get a fair bit of a weld done before it gets too hot to rest on with two gloves."

This is the main reason i cant do long welding runs around the pipe, cos it gets too hot. I will start wearing thicker gloves and start thinking how to make the processes more comfortable and easier.

I will be practicing a lot the next couple of weeks. Should be fun. I have just downloaded a great book, Welding Pipeline handbook. Some very nice illustrations and guides on Arc welding. I got a long way to go so any suggestions and help would be appreciated.

One more question, with S/S when you do the tacks whats the best way to do them, and is it best to do smaller gaps on the S/S pipe? In the test i was getting awful deposits. Can you purge for tacks?



Regards,
Paulo

Yeah, purge wherever you can, and do big gaps for stainless as it grows more than mild when it's hot. grind the tacks back so you have a feathered edge to run off and back onto. I think your tacks have to be under 12mm long. Any time you stop during the root, make sure you grind the gas pore out, just hit the end of the weld with a 1mm cut off disc before starting again.

Where did you get the booklet from?

What code are we working from gents?
6G sounds like its ASME code or standard.

12mm long tacks on a 6 " pipe is a really hard gig.I am sure As1796 allowed more than that.I'll have to dig out the Code.

Make the tacks long enough to include the gas pore etc that must be ground out.

The cut and taper the the tack back to its spec size .In that way you can finish with a ground back tack of the spec size that is 100% sound.

The other thing is to remember not to grind the guts out of the code. Operators tend to forget that the tack needs to retain enough section thickness to retain rigidity.To put it another way ,taper the ends only for run on and run off.

Its been a while so some more stuff should come back to me.
Its been a touch hectic here over the week end and we have't settled as yet

Grahame