if you use E8010 electrode you may land up with cold cracking due to
hydrogen or HIC
On Nov 22, 1:58 am, Shiva <shiva.kuma...@yahoo.com> wrote:
> Dear All,
>
> We are using API 5L X65 Grade SAW pipes of 24" dia and 14.3 mm WT. The
> WPS has been qualified using E6010 (3.2 mm) electrode for root uphill
> and E8010G (4 mm & 5 mm) for hotpass, filling & caping in downhill.
> But during the welder qualification process, we observed some cracked
> joints in RT. The parent metal has been checked for the chemical
> compostion and is found to have % C -0.05%. All other chemicals are
> within the tolerance as per API 5L.
> On further investigations, it was observed in the micro that infact
> several cracks have been developed in the weld metal (both
> longitudinal & transverse). We increased the pre heating from 80C to
> 110C. Even though we havent found any cracks after that still we
> couldnt effectively get the reason for the crack formation.
> The weld metal revealed on the chemical testing the following results,
> %C- 0.16, %Ni - 0.66, % Cr - 0.43 (I can give you more details if you
> require). These % even though slightly on the higher side are still
> within the acceptable limits and dont seem to me causing a serious
> problem.
> What I have observed one thing is the cooling rate, especially E8010
> electrode is very fast. For eg on the filler passes it drops from
> 110-120C to 60-65C even up to 55C after cleaning.
> My question is, do you think using E8010 electrode for a 14.3 mm thick
> pipe (even if it is X65 grade) is advicable? What may cause such a
> fast cooling rate in the pipes? (Inspite of practicably possible
> shieldings have been provided) Most importantly what do you think is
> the major cause of the cracking. I would like to your valuable
> suggestion in this regards
--
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.
Comments