American Welding Society Forum
Guru's in the house, hope we are holding up well during this covid19 pandemic? I know it will surely end soon.
Am currently reviewing a friend company's WPS with a material of API 5L x70 grade pipe, on the section of electrode/filler wire am seeing the used E6010 for the root while the remaining passes the used E9018 G.
My question is why use E6010 for root when the tensile strength of the pipe is 70KSI.
Thanks as I await our contributions and experiences (@Al, Brent and others)
What is the governing welding standard? Was there a supporting PQR?
Governing code is API 1104
He didn't give me the pqr all he said was it passed (though am not their client or anybody in the project).
Am just a passerby, I just wanted to learn more
API is pretty loosey goosey. You can pretty much do whatever is proven via the PQR.
Generally, one would not try to overmatch the base metal by 20ksi. Pipeliners tend to favor an electrode that utilizes a cellulose based flux for the root bead because of it's deep penetration characteristics. Filler metals that are undermatched tend to strain harden when strained beyond their yield point and gain about 10 ksi. Some people call it work hardening, but by any name it gets stronger so that it more closely matches that of the base metal.
Wow loosey goosey lol, now I see why the used E6010. But if it was to be ASME ix would it had been different?
Thanks for the experience shared.
No. Same story there.
to answer your question. They should not have used E6010. E6010 is a 60 KSI material and the X70 pipe is a 83 KSI material. If your friend is under API 1104 then according to API 1104, under filler metal you should be matching as close as possible the filler metal and base metal. Since E9010 is a 90 KSI material it better matches your pipe. Or E8010. A review of the WPS up against API1104 is in order.
Thanks for your info, all along I was thinking x70 has a tensile strength of 70KSI but you just said its 83KSI but my worries are how come my friend claim that the test piece passes mechanical test (according to code) cos its not adding up.
I don't know if I can totally answer that without seeing test documentation and MTR's, but one reason could be the root pass (E6010) typically welded down hill is not much of the weld thickness, and since they used E9010G for the remainder of the weld thickness, could be the reason he is saying it met tensile requirements. (If that is what he is saying) The KSI of E9010G could be at least as high at X70 material and higher. Its hard to review PQR's and WPS's without good information. It's important to have the COC, the PQR (in the case of API 1104 typically the PQR and WPS form are the same) and any client requirements when reviewing a procedure. If you have an ASME Sec. IX a quick reference for materials is found in Table QW-422. Hope that helps.
Thanks once again you have done much already.
Hope you are having a great time (covid19)
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