Sunday, July 17, 2011

Re: [MW:11790] RE: 11741] FCAW for Duplex stainless steel

Dear Pradip:

Correct me if I'm wrong:
1-We want to go with FCAW
and
2-We have chosen our filler metal

Is that correct....?


If it is then:

The point is When a reputed manufacturer claims that their "X" filler
metal can deposit a weld metal with specific mechanical properties,
you should believe that.
I know that I do...!!!

And if required, they will give you neccessary recomendations for
these filler metals.
You can always send them an email and check with them if you feel uncomfortable.

In the Duplex S.S. case, as you know better than anyone, intermetallic
precipitates in H.A.Z. should be our concern and may cause a drop in
CVN toughness below minimum requirements.

GMAW-P is a good choice here. As a matter of fact, I have just
finished a welding and overlay job on Duplex stainless steels with
GMAW-P and everything was OK.

Depending on material grade, setting welding parameters for Duplex
stainless steels when 50J CVN is required could be kind of tricky...
we need more details of the job...!!!

Let's ask our dear friend, Mr.Park to provide us with more details
regarding base metal and service conditions so we can discuss it in a
more precise manner.

Regards
Ramin

------------------------------------------------------------------------------------------------------
On 7/17/11, pgoswami <pgoswami@quickclic.net> wrote:
> Ramin,
>
> Everyone knows that FCAW is a proven established welding practice.However
> it's not always easy to get the correct engineering requirements ,
> especially impact strength in FCAW from the off-the shelf items.
>
> Client's welding engineer has to engineer the requirements , consumable
> manufacturers has to make their products to the required specification.If
> two parties discuss over the issue and comes to some understanding the
> solutions are fast.
>
> By current industry standards it's difficult to meet the impact requirements
> CVN value shall be min.50 Joule at -46 degree C , in FCAW process in Duplex
> S.S, unless the consumable is designed for the same. See the extract from a
> paper of Metrode. The main issue is "Oxygen" in the weld metal. Where low
> temperature impact is are requirement I have seen that many clients prefer
> GMAW-P process over FCAW.
>
> See the API-620,proposed revision for incorporating Duplex S.S, asks the
> fabricators to exercise caution while handling Duplex S.S.
>
> Thanks
>
>
> Pradip Goswami,P.Eng.IWE
> Welding & Metallurgical Specialist & Consultant
> Ontario,Canada.
> Email-pgoswami@ <mailto:sympatico.capgoswami@quickclic.net> sympatico.ca,
> pgoswami@quickclic.net
>
>
>
> _____
>
> From: materials-welding@googlegroups.com
> [mailto:materials-welding@googlegroups.com] On Behalf Of Ramin Kondori
> Sent: Saturday, July 16, 2011 2:06 PM
> To: materials-welding@googlegroups.com
> Subject: Re: [MW:11772] RE: 11741] FCAW for Duplex stainless steel
>
>
> Dear Park:
>
> Just choose a cored wire that meets the requirements and the rest of it
> depends on how you weld it...!!!
>
> I mean if the cored wire has the minimum requirements so you do not have to
> worry about your weld metal properties...!!!
>
> It is the Base metal (HAZ to be precise) that you should be careful
> with...!!!
> And that depends on heat input, it is always our dear friend Mr.Heat
> Input...!!!
> Heat input depends on current and voltage and these two depend on wire
> diameter
> It's better to read about your base metal to see if it is prone to
> metallurgical degrading during welding and if it is you should be careful
> with choosing wire diameter.
> Sometimes even you need to maintain a minimum preheat and at the same time a
> maximum interpass temperature.
>
> if You give me more details I can tell you more...!!!
>
> But do your own homework first...!!!
>
> So choose a wire diameter suitable for your base metal thickness (not too
> small not too big) and weld it with recommended current, voltage and travel
> speed as AWS handbook tells you...!!!
>
> I have attached a scanned copy of the AWS's FCAW handbook for your use. Read
> it it's not too much...!!!
>
> FCAW has no such problems as GMAW has when dealing with Duplex steels so you
> may not face much trouble with it...!!!
>
> Good Luck
>
>
> Ramin Kondori
> QC/Welding Engineer
> IWE AT 0070
> <http://www.twi.co.uk/twiimages/iiw.gif>
>
>
>
> On Sat, Jul 16, 2011 at 8:02 PM, pgoswami <pgoswami@quickclic.net> wrote:
>
>
>
> Hi Park,
>
>
> What's the design code? the grade of duplex S.S to be welded.?
>
> From the face value Kobelco and Metrode FCAW products look good. The other
> alternative could be Bohler-Thyssen. You need to ask the manufacturer
> precisely about your requirement.
>
> To the best of my knowledge FCAW process is not 100% reliable for Duplex
> S.S , when impact requirements are to be met at -40deg C or below.You may
> check the recommendations of API -938C also and get the best answer from
> consumable manufacturer.
>
> Thanks.
>
> Pradip Goswami,P.Eng.IWE
> Welding & Metallurgical Specialist & Consultant
> Ontario,Canada.
> Email-pgoswami@ <mailto:sympatico.capgoswami@quickclic.net> sympatico.ca,
> pgoswami@quickclic.net
>
>
> _____
>
> From: materials-welding@googlegroups.com
> [mailto:materials-welding@googlegroups.com] On Behalf Of ???(PARK, JONG MIN)
> Sent: Friday, July 15, 2011 11:02 PM
> To: materials-welding@googlegroups.com
> Subject: [MW:11741] FCAW for Duplex stainless steel
>
>
>
> Dear Experts
>
>
>
> I wan to use FCAW process for welding of duplex stainless steel.
>
> However, CVN value shall be min.50 Joule at -46 degree C.
>
> Is there any flux cored wire which meets this requirement?
>
>
>
> --
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>
>
>
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> The views expressed/exchnaged in this group are members personel views and
> meant for educational purposes only, Users must take their own decisions
> w.r.t. applicable code/standard/contract documents.
>
>
>
> --
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> For more options, visit this group's bolg at
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> The views expressed/exchnaged in this group are members personel views and
> meant for educational purposes only, Users must take their own decisions
> w.r.t. applicable code/standard/contract documents.
>
>


--
Ramin Kondori
* QC/Welding Engineer *
* IWE AT 0070*
**

--
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For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

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