Ari,
Offshore Pipe industry prefer to use 6010 for root
1.to avoid root defects
2.better ductility than 7010 and 8010.
3.welder friendly electrode
Though electrode is classified under 6010, its UTS and YS will be higher than 70 Ksi.
Regards,
Alagu
On Thu, 19 Mar 2009 Ari wrote :
>
>Dear All,
>
>Can you please advise, why E6010-G (root) & E-7010-P1 (hot/fill) are
>used for Oil pipelines(Sour) containing parent material of API 5L X65.
>Since these type of PQR/WPS are being approved by most of the
>Company.
>
>As, X65 has an YS of 65,000 Psi, whilst the electrodes used E6010 has
>YS of 48,000 Psi, and E-7010-P1 has YS of 60,000 psi. By using both
>of these electrodes the weld metal strength would not exceed YS
>60,000 psi.
>
>How its acceptable to keep the low weld metal strength(<YS 60,000 Psi)
>than the parent metal (= YS 65,000Psi).
>
>Thy suppose to use E8010 for root and E8018 for hot/fill, for API 5L
>X65 materials, which only would give the equivalent WM strength.
>
>As we all know that overmatching weld metal strength causes gross
>section yielding in the pipe, whereas Undermatching weld metal
>strength will cause straining of the weld.
>
>Your advise/suggession, based on experience is appreciated.
>
>Regards,
>
>Ari
>
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