Camilo,
Electrodes kept inside a closed electrode drier will not pick up any moisture before reaching ambient temperature, so in your example below you do not need to redry. It is possible to repeat the operation and return the electrodes to low hydrogen state several times, see my answer below:
The electrodes can be redried several times if the holding time at the
> redrying temperature is respected. 3 times or more should be no problem.
> Up to 24 hrs.total holding time at 350°C is OK.
Regards,
Claes Gillenius
Development Engineer, MMA. (Spec. stainless and non Fe-alloys)
Direct tel: +46 (0)31 509315
Mobile +46 (0)707532012
Company ESAB AB
Address Box 8004, 402 77 Gothenburg, Sweden
Lindholmsallén 9
Company reg number 556005-7738
| "Salvador, Camilo" <cafsss@gmail.com> Sent by: materials-welding@googlegroups.com 2009-09-23 16:28
|
|
I have one question,
SItuation: I open a pack of electrodes. The pack's lost vacuum. So i
redry the electrodes at specific conditions (e.g 350ºC; 2 hrs) and
before that, keep them on a 150ºC electric hot house / electrode
dryer. Ok. Supose that the energy breaks down, and the ambient gets
moisture. Can i repeat the entire procedure and guarantee electrodes
properties? If the energy restart in a few minutes (e.g 20 min) and if
the temperatures variation's not great (- 30ºC), its necessary to
redry at 350ºC?
How many times can i redry the electrodes?
On Sep 22, 5:59 am, claes.gillen...@esab.se wrote:
> Dear all,
>
> Our recommendation regarding storage and handling of low hydrogen covered
> electrodes is as follows:
>
> Electrodes that have been kept in air tight package, i.e. for ESAB vacuum
> packed, which has not lost its vacuum, can be used right away regardless
> of storage time. Electrodes packed in other types of packages should be
> redried before use.
> Redry at 350°C, 2 hrs. or read and follow instruction on the label. Store
> the electrodes after redrying at a lower temperature. Our recommendation
> is 150°C. Note that redrying at lower temperature than recommended will
> not return the electrodes to their original low hydrogen state.
> The electrodes can be kept for a long time at 150°C, without any
> deterioration, but at 350°C, they will slowly oxidize. Do not keep the
> electrodes at that temperature longer than necessary. Our tests have shown
> that after a couple of days at 350°C, basic low hydrogen electrodes start
> to show signs of deterioration due to oxidation. There will be a loss of
> manganese and silicon in the weld metal, which will affect mechanical
> properties.
> The electrodes can be redried several times if the holding time at the
> redrying temperature is respected. 3 times or more should be no problem.
> Up to 24 hrs.total holding time at 350°C is OK.
>
> Regarding maximum shelf life we recommend 3 years, mainly because there
> may have been changes in formulation and properties during that time, i.e.
> the old electrodes may not be the same as what is sold now. For really old
> electrodes it is difficult to find documentation. I would not recommend
> any test type bending or dropping, definitely not for low hydrogen
> electrodes.
>
> Best regards,
>
> Claes Gillenius
> Development Engineer, MMA. (Spec. stainless and non Fe-alloys)
> Direct tel: +46 (0)31 509315
> Mobile +46 (0)707532012
> Company ESAB AB
> Address Box 8004, 402 77 Gothenburg, Sweden
> Lindholmsallén 9
> Company reg number 556005-7738
>
> Shashank Vagal <nach_...@yahoo.com>
> Sent by: materials-welding@googlegroups.com
> 2009-09-22 07:30
> Please respond to
> materials-welding@googlegroups.com
>
> To
> materials-welding@googlegroups.com
> cc
>
> Subject
> [MW:3271] Re: [MW:/] Re: 3238] Shelf life of Low hydrogen electrodes
>
> Raj,
> Thanks, that is interesting. Such practical approaches borne out of
> experience are very useful guidelines.
> SV
>
> --- On Tue, 22/9/09, rajagopal kannan <rajagopal.kan...@gmail.com> wrote:
>
> From: rajagopal kannan <rajagopal.kan...@gmail.com>
> Subject: [MW:/] Re: 3238] Shelf life of Low hydrogen electrodes
> To: materials-welding@googlegroups.com
> Date: Tuesday, 22 September, 2009, 9:50 AM
>
> Dear Shasank,
> As stated in this tread earlier, ASME Sec. IX code does not state anything
> about this. we have to go by tthe manufacturer's instruction only.
> But, I have come across a practice to test its usability. But I can't
> provide you any type of written reference. It was found in one of the
> vendor's system procedures.
> Electrodes considered as old, which doesn't loose flux when dropped
> vertically from 1 meter height from ground is suitable for welding.
> You can try this.
> Thanks and Best Regards,
> K.Rajagopal
>
> On Fri, Sep 18, 2009 at 7:16 AM, Shashank Vagal <nach_...@yahoo.com>
> wrote:
>
> Hi,
> All Ok and accordingly noted. How about the shelf life, if the packing is
> not damaged, do we follow manufacturer's instructions or is there any
> expiry date for it? What is the general approach here, in absence of
> anything else?
> Regards,
> Shashank Vagal
>
> --- On Thu, 17/9/09, claes.gillen...@esab.se <claes.gillen...@esab.se>
> wrote:
>
> From: claes.gillen...@esab.se <claes.gillen...@esab.se>
> Subject: [MW:3240] Re: 3238] Shelf life of Low hydrogen electrodes
>
> To: materials-welding@googlegroups.com
> Date: Thursday, 17 September, 2009, 4:11 PM
>
> If the electrodes are packed in air tight packages they can be used right
> away. If not, redry the electrodes in the way the manufacturer recommends,
> normally at a temperature around 300 - 350 °C.
> Air tight packages are for example vacuum packages. If such a package is
> damaged and the vacuum lost, redy the electrodes. Redrying returns the
> electrodes to it´s original state.
>
> Best regards,
>
> Claes Gillenius
> Development Engineer, MMA. (Spec. stainless and non Fe-alloys)
> Direct tel: +46 (0)31 509315
> Mobile +46 (0)707532012
> Company ESAB AB
> Address Box 8004, 402 77 Gothenburg, Sweden
> Lindholmsallén 9
> Company reg number 556005-7738
>
> "Bathula Raghuram (Mumbai - PIPING)" <R.Bath...@ticb.com>
> Sent by: materials-welding@googlegroups.com
> 2009-09-17 12:17
>
> Please respond to
> materials-welding@googlegroups.com
>
> To
> <materials-welding@googlegroups.com>
> cc
>
> Subject
> [MW:3239] RE: 3238] Shelf life of Low hydrogen electrodes
>
> Consult the consumable manufacturer, may be shelf life revalidated with
> additional testing. Code does not specify the shelf life, but the
> manufacturer does.
>
> From: materials-welding@googlegroups.com [mailto:
> materials-welding@googlegroups.com] On Behalf Of Ravindra T
> Sent: Thursday, September 17, 2009 3:28 PM
> To: materials-welding@googlegroups.com
> Subject: [MW:3238] Shelf life of Low hydrogen electrodes
>
> Dear All
>
> Our contractor has brought low hydrogen electrodes (E 7018 & 8018) which
> are manufactured in 2007 for welding station piping in one of our
> intermediate pump station of our cross country pipeline project. I would
> like to know whether these electrodes can be used now?. Is there any
> reference in ASME code regarding the expiry/ shelf life of Electrodes?
>
> Please advise me in this regard.
>
> Thanking you all in advance
>
> Ravindra
> Senior Project Engineer
>
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