FCAW for piping

By BryonLewis (****)

Date 02-24-2009 03:27

You might ask them.

By Metarinka (****)

Date 02-24-2009 19:34

I remember overhearing that it's use was limited in piping applications due to increased likelihood of slag inclusions over SMAW. I'm not sure if that is accurate or true.

Due to the nature of FCAW wire manufacturing certain SMAW fluxes are not able to be provided in tubular form therefore there is still no way practical way to create the desired atmosphere or alloy content in FCAW wires.

I think some of the reluctance to use FCAW is because it represents a big paradigm shift or breakaway from the comfort zone of the end user, also there are real and imagined disadvantages of the process compared to SMAW.

all this is slowly changing and I FCAW is slowly gaining market share in the United states and abroad due to the economics.

By tc 88 Date 02-25-2009 01:18

was it due to not environment friendly? limited welding position? gas combination for welding may react some of product?

By dmilesdot (**)

Date 02-26-2009 17:07

There are issues with compatability when it comes to a field repair. Typically reparis are done SMAW. Welding over some FCAW can cause hardness issues.

By swsweld (****)

Date 02-25-2009 02:05

It's common in pipe shops to use FCAW, especially with GMAW root pass and welded in the 1G position (or close to it) with a positioner.

If PQR and WPS's are in order there is no good reason not to use it. It is more cumbersome in the field compared to SMAW and therefore risky for some companies.

By Fredspoppy (**)

Date 02-25-2009 17:14

Manufacturing of flux cored wires is not as straight forward as with other consumables and proper care of the filler in the shop or outdoors worksite is very important. As you are aware, there is a longitudinal seam for the entire length of the cored wire (unless it is a seamless tubular wire) makes for the possibility of moisture pick up. This is a big problem where base material sensitivity to hydrogen is a factor. Where clients do allow FCAW, you may still have manufacturer and trade name added as essential variables into the Clients Fabrication Specification.

By Nanjing Date 02-26-2009 16:46 Edited 02-26-2009 17:03

It takes a lot of skill to weld a pipe with FCAW. It is ideal for "flat bashing" in structural steel applications when you want it welded quick and not so particular with appearance. It tends to turn out pretty lumpy in unskilled hands. I think whether the wire is seamless or of folded construction is not a major issue. Consumable manufacturers will give you the hyrogen content for their wires and this should be no problem if you follow their reccomendations on consumable control. I think I am right in stating seamless wires are copper coated and run through the wire feeder better however from the engineering aspect the thickness of the sheath is thicker compared to a folded wire therefore the deposition rate will be slightly less due to the influence of current density. Another aspect is, how do flux core wires get their great properties? Look at any manufacturers data sheet and they will give you the C Si Mn P and S content. Where do they get their strength and toughness from. They do not tell you about the microalloying that goes into them mainly Titanium and Boron. Has anyone run a stress-relieved procedure in the past and had problems especially with their charpies ? A number of major manufacturers are now marketing stress relievable wires but I have never tried it. Anyone out there done it?

NKG

By Chin Terry (*)

Date 02-27-2009 01:09

in term of workmanship we need higher skill, how about in term of commerical? which process (SMAW or FCAW or GMAW) more economic base workshop and field fabrication work?

By Nanjing Date 02-27-2009 13:52

Not really so simple to answer but I think the bottom line is it all depends on how much money you want to invest and how much confidence you will have in getting a return on your money. FCAW will increase your deposition rates over the other two processes so it would make sense to use this to reduce your labour cost but it will mean you have to fork out more money to buy the welding plant.

By rodofgod (**)

Date 03-03-2009 00:01

Hi All!
I live and work over the water in the UK and was amongst the first to use FCAW in power station repair work. At first, all was good, everyone came to see main steam header's welded up very quickly and the client was happy! No repairs and good heat inputs! Then every tom, dick and harry was filling and capping with flux cored wire on anything above a certain size, with very little training, if you could MIG weld then you could use FCAW?! All of a sudden, the repair rate shot up, due to lack of training and poor selection of welders trained to perform these high quality welds! Also, it must be said , down to the increase in poor wire that flooded the market.
I am no longer welding for a living but based in an office and still get negative feedback about FCAW, and no matter how hard I proclaim its virtues, I still get a negative response.
Nanjing, both ELGA and METRODE produce a FCAW welding wire that is stress relievable, the ELGA one, I have just finished a contract on a major LNG project and can confirm works as stated!

Regards