High Speed mig and TwinPulse on CrNi

[matt1978]

What you describe is very simerla to Cold wire and Hot wire tig, which is available now......has been for about 18yrs.....on the Lorch system you can get the wire to Pulse in and out of the weldpool in time with the Pulsing of the welding current.

The downside to it, is you need very good/big torch access because fixed to the tig torch is a wire feeding tube and it makes the end of the torch quite big

 

[astro_al]

Oh well - I'm behind the times! (To me a Dialarc is new and cool! )

Yes sure its a bit like having mig and tig in one torch, so a bit cumbersome. Anyway, I'll stop polluting this thread with my brainfarts. great stuff - keep it coming!

Thanks again. Al.

 

[snowcat]

This system can/has replaced a lot of tig applications, but there will always be applications for Tig welding, either when a really really high quality is required, a really small sized weld, or if the fit up is not very good etc

We also do a Cold wire tig system, that uses conventional tig but the filler wire is automatically fed into the pool

Pahhh at the risk of sounding a bit too UKW, the reason these machines replace TIG is simply price, yer man looks at the cost of training someone to TIG, plant then speed of weld, over a Monkey with a syn'g machine, one skilled setter among half a dozen Monkeys...running very quick beads in..and £££££££ notes start to flash...

Its the same with MIG over ARC, both TIG and ARC are and always will be far more versatile and providing better more constant welds, but far more skilled and more time consuming to use, hence the reason for the fall in popularaty....luckly weld inspectors are still to be convinced (cold lap one issue) about some of the welds produced by these machines......

 

[matt1978]

Yeah that's exactly why I said if you want a very high quality weld then use Tig every time...at even more risk of sounding UKW, I am/was a time served (at Babcocks) welder to Nuclear standard on Tig and MMA before I got into sales, so it makes no odds to me what the end customer wants to buy, I can sell him any machine/process (MMA,TIG,Mig) and give him benefits with our kit over and above what he is currently using in a lot of cases.

The reason Pulsed mig replaced a lot of tig work is because with recent advances its a bit easier to get comparable results (not as good) as tig on some applications with the mig process than it is with tig purely from a operator skill level.

There has been a bit of a new interest into welding and fabricating in last couple of years but in the last 10 yrs and more young kids didn't want to get into welding or fabricating, it was all office work and computers, so there is a very low skill level out there now because skilled guys have retired/left the industry/or diversified and not been replaced, so its not all the greedy boss trying to make extra money by lowering quality and using mig to weld stuff faster.....that does happen but in most cases, its because the boss can't get enough skilled tig welders.

Your right about some weld inspectors, but I wouldn't offer that process if I didn't think it would be an advantage.....When I was at Fronius we worked on a project at Cranfield University for welding oil pipes together, using Twin Wire mig (2 wires in one weld pool) and we sold 100's of systems in the USA for a pipe line running all the way from Alaska to the states.....the mig quality was perfect....there's no way you could of tig welded the joint as it was Narrow gap........only about 30mm prep and the joint was about 150mm deep......all to Ultrasonic testing

All I am saying its horses for courses........if you have got to weld a a load of stainless pipework up to x-ray standard then I will sell a tig machine......but I would also sell a Pulsed mig for all of the ancillary stuff, like bracketry and slip of Flanges etc......where as before even these may of been tig welded

And one last thing, anyone can pick up a mig torch and pull the trigger.........but you have still go to be a good welder to produce good welds........even with Mig

 

[snowcat]

Was feeling particularly peeved when I wrote that last post Matt as everything has not gone My way Tday...

Your Right about the lack of Skill level Much of the Rot (and not just in our industry) happened when I left School, No apprenticeships, along with teachers (who I guess don't really know the world outside academia)pushing us to do office work, or A levels followed by University, any other alternatives were hardley mentioned, and as a result skilled labour has become a premium..........

The Issue I have with MIG is not the process at all its simply the poor training that runs with it, both Stick and TIG take years before a skill level is set, with a MIG its Days sometimes hours before decent looking beads are made, So as soon as Jack the lad can Run a pretty looking bead on a couple of bits of plate, then hes a welder......never mind about pen, distortion, crystalline structures, carbon % etc etc..........because its quick to learn the basic fundamentals of the job also seam to get skipped as will..

I think the Fronius Machines Iv played with are great, and have toyed with the Idea of buying one myself, but realistically Id have little use for It.... Really is horses for courses as you say, much of the work I do is 1offs or refurbs, and in that environment I think Arc, TIG, and MIG for the light sections is unlikely to get replaced.......

 

[matt1978]

No prbs mate, sorry that you have had a bad day...

Mig is definitely the easiest process to learn and I suppose the easiest to pull the wool over someone's eyes, but as with anything Structural, where there has got to be some quality attached to the welded joint.....people like that easily get found out....unfortunately is usually too late by then.

There is a huge skills shortage in our industry as we have said mig is the easiest to learn....but you would be amazed at how many so called welders can even set up even a basic Transformer mig correctly.

 

[shenion]

matt, that Cranfield University job, I assume that is robotic welding?

 

[matt1978]

Yes Shenion, it had about 4 welding heads (each with 2 wires) on each joint........the Automatic side of it was done by a Texan company.... CRC-Evans http://www.crc-evans.com/news-body.htm

They moved the wires rapidly from side to side to ensure good side wall fusion....I think it was the first Narrow gap welding to be done.

The smaller weld prep saved 1000's of Kilometres of weld compared to conventional method.

 

[astro_al]

Urg. I spent 3 years at Cranfield - possibly the most depressing location on planet Earth.

Were you resident there Matt, or just working with them?

Al.

 

[matt1978]

No just working there mate........to be fair it was more my colleague than me, but I helped him out over there a few times.

The guy from Cranfield who came up with the idea for the process was called Dr Stephen Blackman.....did you know him?

 

[astro_al]

Consider it a near miss!

No - different department I was doing space eng stuff. I did wander round the welding dept once though, I wish I'd had the interest in it then that I have now - it was all interesting at the time, nowadays they'd probably have to give me oxygen and carry me out on a stretcher.

Cheers, Al.

 

[matt1978]

If you ever get chance, you should go to the TWI, The Welding Insitute in Abingdon. They have a lot of great stuff there........Lasers, Friction Stir welding etc etc.

 

[astro_al]

Yes, but do they allow weirdos like me inside? Its not far away...

Al.

 

[matt1978]

I don't know how it works with the General public, whenever I have been its always been work related.

There maybe issues with Insurance and public liability, but I am sure they must have open days etc.

Have a look on there website.

 

[Rusty]

Very interesting and well written matt1978.

 

[matt1978]

Very interesting and well written matt1978.

Cheers mate

 

[snowcat]

If you ever get chance, you should go to the TWI, The Welding Insitute in Abingdon. They have a lot of great stuff there........Lasers, Friction Stir welding etc etc.

I went there not long ago to learn all about stress reversal, and Computer prediction of it, lots of picture's of red, green and blue structures....

 

[matt1978]

How did you get on? What did you think of it snowy?

 

[snowcat]

burning the midnight oil matt?? Very intresting..... It was a trip via a Friend, who had dealings with a company who were using the Institute to get them up to speed on some frames they were making, There earlier work had stress cracked and failed, because of design issues, the institute (as you probably know) has systems which will look at a design then work out associated stress on each part, and convert it to a time line of faluire...... It was the reverse stress that causes all the damage If stuff can be designed to have a continual stress in one direction then it lasts a hell of a lot longer.....

We didn't have time to have a proper look round, (would like to at some point)......as we had to go and see the guys who were using the info, unfortunately when we got to there "shop" we saw nothing but pretty frames going to the paint shop as they had subbed all the work out to the Ukrane.....Grrrr

 

[storm monkey]

We had a visit from our Tec centre structures Guru yesterday, and he mentioned a new process they have been working on (new to them, not sure about the rest of industry). Basically, it's a laser mig method, that has a combined head and puts down a laser weld followed by a conventional mig weld over the top. The advantage is you can weld upto about 14mm plate, full penertation, with no joint prep and minimal joint, at very high speeds. Anybody heard of anything like this before?

Phil