Metal Core Wire

Date 05-01-2003 01:03

John,
We haven't used metal cored wire yet. One reason is that we work on a wide variety of projects, from bridges and structural, to tanks, to repairing our own clamshell buckets. We have found that sticking to one wire and process that is tolerant of a wide range of condition has been the most sensible option to date.
Some salesmen have tried to convince us that we'll save megabucks in gas consumption, wire consumption, and productivity but the trial samples we have used fell short of the promises. Possibly, a long term test would back up the claims but we have been leery of the education process in re-training people. (In our shop, the fabricators are also the qualified welders so that means everybody.)

Chet Guilford

By jwright650 (*****)

Date 05-01-2003 11:24

Chet,
One thing that I was looking at is the fact that everyone (like in your shop) has to be qualified in GMAW. I know that's part of my job here at the company, but it seems like alot of work (new WPSs, certs, etc), if it is not all that great after we go through piping the shop for Argon/CO2 mix and all that. Our other plant is brand new and they are still excited about being in a new (very,clean) shop, and the decision to change all that over was easy to do in their situation. We are in a cramped 35 year old facility that has been added on to over the years and isn't laid out that great, yet we are consistantly running more tonnage thru than they are with all that new state of the art equipment(lots of automation). I'm talking 500 tons/week vs 200 tons/week, that's hard to justify spending $'s on when what we have for the moment is working better, even with all that old equipment. I'd like to see us swap shops and see where the tonnage/week numbers go. I think we have a great bunch of guys here.
Sorry for the rambling(and boasting),
John Wright

By rodofgod (**)

Date 05-02-2003 01:49

My company has all the WPS's for metal cored wires and still, we use flux cored for the majority of our structural work!I don't think[at the moment]the outlay is worth the rewards in term's of increased production.

Glenn Webb

By CHGuilford (****)

Date 05-02-2003 14:02

John, it sounds like in your situation, if it isn't broken, why fix it? I don't know the actual numbers right now, but i don't remember metal-cored being that much higher in deposition rates than flux-cored. At least when you compare apples to apples and run similar amperages and all that.
I guess metal cored "appears" to be cleaner but as I noted in a recent post you are still getting metal fumes, and ozone at a higher level. So when doing a comparison, is metal-cored any safer just because you can't see the contaminants that are still there? I feel good ventilation (dynamic air flow) should be a requirement for any welding and if it is provided, flux-cored shouldn't be any more dangerous than any other process.
I think many people fail to look at ALL the associated costs in changing over to other processes. Time and $ for PQRs, time to adapt, special piping and equipment, training, higher level of rework for a (hopefully) short time are all measurable costs that often are ignored when comparing deposition rates of filler metals.
I don't know about your shop, but our welders average 1 hour of trigger pulling arc time during an 8 hour shift, and that isn't slacking off. That tends to shrink the true cost advantage in changing wires. And then you have to consider the versatility as well.
Also, if your shop runs like ours, for any change you make, half the people love it, half will hate it, and many will spend their waking moments debating the issues they really can't change anyway (does that sound too cynical?). Either way, quality and production will suffer, that's a given. What the decision makers have to decide is if the change is worth it. In my book, changes have to be justified.
(Of course decisions like that are easier if the vendor will help defray the changeover costs but 100 lbs of free wire doesn't quite cut it.)

I guess I get too opinionated at times, sorry for MY rambling.
Chet Guilford

By JTMcC

Date 05-02-2003 15:27

1 hour per 8 hour shift? Do your welders work as fitters also? Our work is mainly in the field and piping or piling related so I probably don't understand all of the factors involved but I would be interested if you could elaborate on the reasons for so little actual welding time. Thanks,
JTMcC.

By jwright650 (*****)

Date 05-02-2003 21:47

Yes, our fitters also weld, so our actual welding time per hour is low as well.
John Wright
Thanks guys for your input, I visited the new shop today and now I'm envious of those guys down there(great big clean shop). I saw the metal core wire in action and there is almost no smoke what so ever. It looks like their welders haven't got the hang of that wire yet. Our welds in our shop look alot better. There was no splatter to speak of. Our guys can run flux core with out alot of splatter too, but that metal core is a little cleaner when you consider only silicon to chip off instead of a thick layer of slag. I did like the way they had hung their welders on a jib where there is no cables in the floor. The jib will swing out over their tables and reach anywhere around the area. All the gas is piped in and no bottles to change. I'll do some more research before we jump into anything. Thanks again.

By CHGuilford (****)

Date 05-03-2003 14:28

That's correct that our welders are fitters also, same as John mentioned.
Some time ago, I had put a data logger on the welding machines so that we could see just how much trigger time our employees were doing. The average was pretty fair and done over a couple of months. Some people were fabricating structural steel which involves a bit of handling, getting the parts from a rack, reading the prints, laying out anything the machines didn't do, setting and tacking the parts, welding one side, flipping the beams and welding the other side, tagging, and moving to the "done" pile. And those guys were working at a good pace.

A few people were welding inside and out of a jacking frame that had already been fabricated but had a lot of welding to do in multi positions. Basically they got inside a "boxed area" (but not a confined space situation), welded everything within reach, and moved on to the next section. It was interesting that their trigger time was only 1.5 hours in a 10 hour shift but they were really busting butt, competing with each other to see who could do the most.

That's why I am skeptical about claims of huge gains in productivity with new weld wires. I know there are some welding situations where the welder can put down a lot more wire than we do. But I've been in and visited many other shops. Everything in nearly the same everywhere from what I've seen. The long and short of it is that welders are expected to do much more than lay down beads. Setting up, adjusting for conditions, chipping and cleaning, and other duties and coffee breaks all eat up time, but are all very necessary steps.

The highest welding rate I have seen from a human was on PQR test plates, 30" long by 1.125" thick. That ran about 1.25 hours welding out of 3 hours total for the plate. But the welder was very fatigued so the next plate ran 1.25 hours out of 5 total. Even though that was all pre-fitted parts welded on a bench with a stool to sit on, heat and fatigue took their toll.

I probably gave you more than you were looking for, but that's what I base my comments on.
Chet Guilford

By JTMcC

Date 05-05-2003 17:00

Chet,
That's very interesting to me and definitely not too much information. Almost all of our work is in the field, mainly on pipe, and we keep our welders busy welding as they are too high priced to have them doing other jobs. Fitters and welders helpers perform most other tasks at a much lower hourly rate. Of course conditions vary from job to job, and day to day, but we do try to keep the welders welding, at a rate of about 50% of the time. During that other 50%, they are in effect resting, as the fitters and helpers are doing their thing so's the welder can get back to welding, or driving to the next location. Our welders are rig hands, which makes them even more expensive when they are doing things other than welding or burning. They are expected to make 100% X-ray all day long so we don't ask them to grind, fit, ect.
regards,
JTMcC.

By TimGary (****)

Date 05-02-2003 20:45

Hi John,
I haven't used the metal core yet, but I thought I might share some info I received at a PRAXAIR Cost Effectiveness/Welding Fume seminar attended last year.
To make a long story short, they claimed the following benefits from metal core wire and Argon rich shielding gas combination versus flux core with CO2:

50% reduction of fume generation.
30% higher deposition rate
70% decrease in shielding gas usage
Greatly reduced spatter
Elimination of slag chipping
Increased control of weld bead size
25% increase in travel speed

They also put a lot of emphasis on the point that OSHA is about to come out with greatly reduced Permissible Exposure Limits, concerning welding fumes. Evidently the old PEL were developed in 1970 and are about to be updated. This would supposedly cause most shops to either install extensive fume removal systems, or change processes, or both.

Of course this is all hearsay, so don't take it as gospel.
One thing I do know for sure is that the metal core wire costs twice as much as the flux core.

Tim

By bmaas1

Date 05-03-2003 17:58

I have used metal core wires before and they are nice.
Pretty much every comment made is correct(fumes, cleanup, dep. rate, etc). I feel the wire cost and amount of actual trigger time doesn't really justify the switch, unless possibly for automatics or robotic applications.

Brian Maas

By jwright650 (*****)

Date 05-05-2003 15:02

Hi Tim,
I went to a Praxair seminar here in town several months to a year ago and I do remember that they pushed the OSHA data at you pretty hard. At the time I talked it over with the powers in charge and no one would even consider the change over from flux core to metal core. I do like being able to see down thru the shop bay on a humid or rainy day, that is a plus. All that slag from our flux core has to be swept up everyday. Those air chippers are very noisy on light beams or tubing. Our CO2 is bottled and kept on each welding machine, unlike the MAPP and OXYGEN that is piped in from bulk tanks outside. I might try switching a couple machines and see how it works out, before spending a lot of time and resources switching over the whole shop.
John Wright
Again, I appreciate the responses and they all give me something more to consider concerning this wire.

By jwright650 (*****)

Date 05-15-2003 17:20

Update:
ESAB is sending out a rep to help us set up two machines (one table with a welder and a fitter) with metal core wire and the proper mix in gas. They are due to be here on Wednesday May 21. After we have given the wire a good look over, I'll try to post my opinions of how the stuff runs for us.
John Wright

By brande

Date 05-25-2003 05:30

While there are some small advantages to metal core, in certain apps, I can't see all the hype.

As far as my experience...the cons...
Metal core does not fill as good as flux core at given amps/volts.
Metal core often requires more expensive gas mixtures than flux core.
Metal core runs hot like solid wire spray arc. This is sometimes not desirable.

The pros...
Slag does not be removed between passes. This is not a real pro as flux core can go pass over pass with no slag inclusions if parameters are right.

FWIW-I think the push to metal core was and is a marketing thing pushed by the wire manufacturers.

Try both- I think you will find the same results.

Good Luck
brande

By jwright650 (*****)

Date 06-09-2003 17:10

So far my welders do not like this wire. One welder is complaining of headaches and another simply took the stuff(ESAB 1/16"dia. Coreweld Ultra) off his machine and put the old flux core wire back on and switched the gas back over. He never even run half of the 60# coil out. It is visibly brighter, shade 11 or 12 is a must in your shield. The heat is noticibly hotter on your hands than fluxcore. The silicon slag is fairly easy to get off, but we never had trouble with the fluxcore slag either, most of it will peel up like a 7018 SMAW rod when the v/amp gets set right. They like the ESAB .052"dia. Coreweld C6 better, but still like the fluxcore better. The C6 beads looked better and wetted better at the toes. Let you know more when we have run more of it.....
John Wright

By DGXL

Date 06-09-2003 20:24

John:
Watching all of the posts on this subject the last few weeks brought me to these few thoughts:

If your running FCAW (S or G), why fix it if it ain't broke?

I have convinced several of my clients to switch from solid wire GMAW to the metal cored electrodes which they all enjoy and like the change. If a client is using FCAW, I don't try to convince them to switch for the reasons you mentioned. Many welders don't like change, I myself enjoy the technological advances being made everyday in this industry.

However, with SS for instance, I had a client purshase a spool of SS metal-cored wire. Not only did this wire save [substantial] time welding, warpage was reduced dramatically and he quit complaining about the $600 spool of wire the first day it hit the floor. Much is dependant on the application involved.

You guys fabricate primarily fabricate structural steel, so;
why fix it if it ain't broke?

(I'm waiting for RonG to get hold of this one... ;-])

By cawelder (**)

Date 06-09-2003 23:43

I have yet to use this wire. How does it do out of position? Meaning Verticle horizontal and overhead. And is it as strong as 71M with CO2.

By jwright650 (*****)

Date 06-10-2003 12:30

cawelder,
It doesn't run out of position very well. Not at all, with out a pulser to help freeze the pool quicker. The bigger the wire the less angle out of position you can run.This is very hot and fluid, it does not have a heavy slag to act as a dam to hold the molten pool until it freezes enough to run it out of position. My guys do not like it and would not run a complete 60# coil before switching back over to Flux core. With this wire the joint "MUST" be completely clean, "NO" mill scale or rust at all, not even a light mill scale. Flux core will perform a lot better in these conditions and give satisfactory results. I know, you aren't supposed to weld over mill scale, but how many people do you think grinds or blasts every fillet weld joint? Fillet welds at base plates and groove welds must get ground, but most fillet welds don't always get cleaned to perfect conditions every time.

I will say that every one should at least try Metal Core wire, because it might work better for other shops in other conditions. For our shop, as others have stated in earlier posts, if it ain't broke don't fix it.
John Wright

By CHGuilford (****)

Date 06-10-2003 13:13

John,
Not to be smug about it, but I kinda thought you would come to that conclusion.
I'm sure metal cored has advantages in some applications, but not necessarily for what I call routine structural fabrication. (Which means a lot of out-of-position welding on everything from 14 gauge to 3" thick.)
Thanks for posting your findings.

Chet Guilford

By jwright650 (*****)

Date 06-10-2003 13:29

CHG,
You know, I looked into this because our welder/fitters got to go to our other plant (brand new facility) and they saw the guys welding with only a whisper of smoke and had to have it. Remind you that the ceiling height in this new plant is over fourty feet and ours is maybe twenty-five or so and that makes a big difference in the apperence of how much smoke is being produced. All of their welding equipment is new and hangs off small jibs that swing out over the work areas. They have a policy of blasting every stick of steel that enters their shop and this is advantageous for the metal core wire. So, upon returning from a tour through this new plant, I was bombarded with ideas of switching over to metal core wire so they could "live 20 more years". I was "robbing 20 years from their lives by making them use this old flux core crap". So, I gave it a try and I don't regret trying, because they now want the old flux core crap back.
Funny how opinions change so fast, huh?
John Wright

By CHGuilford (****)

Date 06-10-2003 16:10

John,
Been there, done that! Only usually I get it from higher ups that have visited other shops and want us to try things the other way. I don't mind trying new things, that's how we all learn, but usually they are comparing apples and oranges.
My prediction is that in 2 or 3 years, someone in your plant will want to try metal cored again.
Again thanks for your postings.
Chet Guilford