hermetically sealed containers, no re-drying or re-baking is required. In the US it is typical for all low hydrogen electrodes to be shipped in such containers. Additional drying typically is detrimental to the coating and should not be performed needlessly.
1. Hermetically sealed containers are not manufactured /available in most of the parts of Asia. They could be common
in US but, imported on a larger shipment basis only into other countries.
2. Even the hermetically sealed containers, when opened and exposed to atmosphere for more than 6 to 8 hrs, may
require additional drying if it is suspected of picking up moisture.
3. For non-radiography quality joints (say, structural) hermetically sealed are not used due to its high cost factor over
normally packed electrodes.
4. Only E 6010, E6013 and other typical type of electrodes do not require re-drying at any time.
5. This is the reality.
.
I have been told, that in some places, low hydrogen electrodes may be shipped in the "green" condition to minimize damage to the coating due to rough handling. If electrodes are in such a condition, only then is drying of the as received electrodes required.
This is why re-drying is done, as most of the manufactures use card board boxes (which are said have 6% moisture content i.e., equivalent to 20-30 ml of H2 and more than specified quantity of diffusible hydrogen level) for packing. Prevention of defects are cost effective than waiting for it to occur.
sridhar.
------------------------------------------------------------------------------------------
From: John Henning <jhenning@deltak.com>
To: materials-welding@googlegroups.com
Sent: Thursday, 19 July 2012 9:16 PM
Subject: RE: [MW:14902] Diffusible Hydrogen Test of Low Hydrogen Electrode
These replies are incorrect.
Please review the highlighted sections of the attached portions of A/SFA-5.1 and A/SFA-5.01, procurement guidelines.
In general the filler metal manufacturer only needs to perform testing on a representative lot of material. As long as the manufacturing process does not change, additional testing is not required. Unless specified otherwise in the purchase order, material will be supplied per Schedule 1/F of Table 1 in SFA-5.01.
If you want specific heat/lot testing you must specify that in your purchase order. You will pay extra for this paper (even though it is more than likely that the filler metal manufacturer has already performed it as a part of their routine).
Regarding re-drying or re-baking. If the electrodes are supplied in hermetically sealed containers, no re-drying or re-baking is required. In the US it is typical for all low hydrogen electrodes to be shipped in such containers. Additional drying typically is detrimental to the coating and should not be performed needlessly.
I have been told, that in some places, low hydrogen electrodes may be shipped in the "green" condition to minimize damage to the coating due to rough handling. If electrodes are in such a condition, only then is drying of the as received electrodes required.
John A. Henning
Welding & Materials
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of c sridhar
Sent: Thursday, July 19, 2012 2:46 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:14900] Diffusible Hydrogen Test of Low Hydrogen Electrode
Sent: Thursday, July 19, 2012 2:46 AM
To: materials-welding@googlegroups.com
Subject: Re: [MW:14900] Diffusible Hydrogen Test of Low Hydrogen Electrode
If the diffusible H2 content specified in the TC falls within the allowable range and acceptable no need to check in every batch.
If the TC values are questionable or if the cold/H2 cracks are noticed often in the weld or if the job is sensitive type, you can cross check the values once in a while.
But, it is mandatory to to re dry/bake all the LH electrodes in the electrode drying oven prior to its use to reduce the moisture content in the coating and reduce the hydrogen level .
sridhar.
From: prem nautiyal <prem_nautiyal26@yahoo.com>
To: materials-welding@googlegroups.com
Sent: Wednesday, 18 July 2012 10:33 PM
Subject: Re: [MW:14892] Diffusible Hydrogen Test of Low Hydrogen Electrode
To: materials-welding@googlegroups.com
Sent: Wednesday, 18 July 2012 10:33 PM
Subject: Re: [MW:14892] Diffusible Hydrogen Test of Low Hydrogen Electrode
Yes. Every low hydrogen electrode e.g. E7018, Batch Test certificate must specify this value. Almost all the reputed consumable manufacturer's check the diffusible hydrogen and report the values in their batch TC. Please refer Table 11 in SFA-5.1 of ASME Sec. II-C. Also if you have specified the diffusible hydrogen content requirement in your welding consumable procurement specifications then it is mandatory for consumable manufacturer to report the values. Regards Prem Nautiyal
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