it is mentioned below that X70 pipe was root welded with E6010, frankly speaking this is a poor welding practice.
Do you have a qaulified PQR for the same? even if it qualified, there are every chances of delayed cracking, Several research has demonstrated that even when using safe welding procedures with proper prehean and intepass temperature in ried condition, it was possible to induce wel metal cracking due to enriched weld metal composition (increase in CE, C%, Mn% and Si%).
As u know E6010 is cellulosic electrode, deliver deep penitration an have the ability to dig through rust, oil, used for joint tight fit-up, provide digging arcs to provide enough penetration but has a disavantage having excess of H2 and fast freezing arc.
An imprtant thing to note is that E6010 is good only for -29 degc, if your design require impact @ -46 degc then you might end up having failure in root (for thickness> 19mm, CVN @ root is required).
I would suggest to use E7016-H4 for root pass with better impact results (low H2 with vertical up capability).
Forgive me if all your questions are not answered, and feel free to ask again if any etail is required.
Regards
Manpreet Singh
On Thu, 21 Apr 2011 13:45:31 +0530 nani grandhi <nani04335@gmail.com> wrote
>Dear sir,
>
>i am very much happy to get reply for my question,
>sir i got reply for my question but the answers i am getting are out of point......
>
>
>it means that
>
>
>
>i am getting the answers for - what are EXX10 electrodes??? and why they are calling cellulose electrodes??????
>
>
>
>but my question was this why E6010 electrodes are called as deep penetration electrodes & why they are using for welding of root only?????
>
>
>Now i will give an example to get clarity for my question!!!
>
>(i.e) for welding of Gr.x70 pipe in pipeline laying
>As per WPS we follow Electrodes are
>
>E6010 is used for root & E 8010G (or) E8010P1 is used for other passes respectively...
>
>here smys of Gr.x70 pipe is 70,000psi (appx)
>
>& UTS of E6010 electrode is 60,000 psi & E8010G (or) E8010P1 electrode is 80,000 psi
>
> we use E8010G (or) E8010P1 electrode to weld Gr.x70 pipe in pipeline which is acceptable because strength of electrode is greater than that strength of pipe.
>
>now
>
>coming for the same analysis for E6010 electrodes
>then the above rule is violated & which is not acceptable in the case of welding.
>
>
>but we prefer to weld (root) with E6010 electrodes, Because these are said to be known as "DEEP PENITRANT ELECTRODES" & specially designed for root only.
>
>
>
>NOTE: Here this case fallows for all Grades like Gr.x70,65,60,52,B etc......
>
>
>
>now here i am interested to know that " E6010 electrodes are said to be known as "DEEP PENITRANT ELECTRODES"??? Why these electrodes are specially designed for root? what type of speciallity's are containing these electrodes when compared to the other potassium, cellulose electrodes? Is any differentiation absorbed in their chemical composition " ?
>
>
>
>Now i hope that i have given clarity in my question, if any doubts in my question plz give me mail so that i will try to explain my question more briefly???
>
>Dear experts i kindly request u people to help me to know the answers for my question!!!!!! i will be waiting for Ur's valuable answers for my question?
>
>
>
> With Thanks,
>Ratnakar Grandhi,
>Gammon India Limited,
>Harayana,
>09996786895
>
>
>
>
On Thu, Apr 7, 2011 at 11:32 AM, JASPAL SINGH <jaspaldhesi@gmail.com> wrote:
>
>
Cellulosic electrodes have coatings or cores with high cellulosei
>contents providing deep penetration and hence are termed as Deep
>penetration electrodes.
>The coating of these electrodes contains organic materials that turn
>into gases in the arc. About 30% of the coating weight is cellulose.
>In some countries, paper pulp and wood powder are added to the coating
>in certain ratios to reduce the amount of pure cellulose. These
>organic compounds in the coating decompose in the arc to from carbon
>monoxide, carbon dioxide and hydrogen, which increase the arc tension
>and thus, the welding arc becomes stronger and harder. Compared with
>other types of electrodes, with the same current values, a 70% deeper
>penetration is obtained with cellulosic electrodes.
>
>
>Regards
>
>JASPAL SINGH CWI-AWS, CSWIP-3.1
>Quality Assurance-ISGEC-PED,
>Yamunanagar, Haryana (India) PH: +911732307251;
>Mob. +918930111441(CUG), +919996624244
>> From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of nani04...@gmail.com
>
>On Apr 7, 1:35 am, "John Henning" <jhenn...@deltak.com> wrote:
>> I am old enough to remember when Lincoln ElectricÒ had propriety labels for their electrodes such as fast freeze, fill-freeze, fast fill etc. These aptly described their solidification characteristics and welders knew instantly what to expect. EXX10 electrodes are what Lincoln called fast freeze - with a primarily cellulose covering, shielding is provided by CO2 generation and a very thin slag. Because of the thin slag the weld puddle solidifies much more quickly than other electrode types (except EXX11 which have similar solidification characteristics). When welding open root, this rapid solidification makes possible bridging of gaps and carrying a keyhole when used with a whipping motion. The depth of penetration is not an issue, but actually is beneficial in assuring complete penetration and allowing for minor deviations in land thickness. Over the years electrode manufacturers have tailored the flux (covering) composition to enhance the performance with respect to open root welding of pipe by small additions of iron powder and arc stabilizers.
>>
>> The downside to these electrodes is the production of copious amounts of diffusible hydrogen and problems with cold cracking. In addition, the rapid solidification can result in significantly harder HAZ's and weld metal. The weld bead is also less visually appealing, usually being coarse and rough.
>>
>> Hope this helps let me know if you are still unclear.
>>
>> John
>>
>
>> Sent: Wednesday, April 06, 2011 9:46 AM> For more options, visit this group's bolg athttp://materials-welding.blogspot.com/
>> To: materials-welding@googlegroups.com
>> Subject: [MW:10607] deep penitrent electrodes
>>
>> Dear Experts,
>>
>> All 90% of pipelines in SMAW E6010 is using for root & others for other passes depends upon strength criteria!!!!!
>> E6010 electrode is used for root because these are said to be known as "DEEP PENITRANT ELECTRODS" & specially designed for root.
>>
>> Now my question was why these E6010 electrods are said to be known as "DEEP PENITRANT ELECTRODS"??? Why these electrods are specially desinged for root? what type of speciallity's are containing these electrods when compared to the other potassium, celleous electrodes? Is any differentation absorbed in their chemical composition?
>>
>> Dear experts i kindly request u people to help me to know the answers for my questions!!!!!!!!!!!!
>>
>> With Thanks,
>> Ratnakar Grandhi
>>
>> --
>> To post to this group, send email to materials-welding@googlegroups.com
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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.
>
>--
>To post to this group, send email to materials-welding@googlegroups.com
>To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
>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.
>
> --
>To post to this group, send email to materials-welding@googlegroups.com
>To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
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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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To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
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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