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_sam@yahoo.com> Sent by: materials-welding@googlegroups.com 2009-09-22 07:30
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| 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.kannan@gmail.com> wrote: From: rajagopal kannan <rajagopal.kannan@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.
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