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
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of nani04335@gmail.com
Sent: Wednesday, April 06, 2011 9:46 AM
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
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