X-65 pipe welding

Date 02-10-2006 17:26

We have to weld API 5L X-65 pipe to a part that requires PWHT. I finally got the MTRs for the X-65 pipe, and it appears that the pipe is in the "as-rolled" condition. If the X-65 gets PWHT at 1125F, will that reduce the properties too much? we only have to meet the tensile properties (and bends), CVNs are not required. I cannot get ahold of the mill, as the pipe was customer supplied, and might have been made in Vietnam. Not sure on that one. If we can't PWHT the X-65, we may have to butter-PWHT then weld to X-65 without PWHT, but I'd like to avoid that if I can.

Chem of pipe is as follows: .067C, .239Si, 1.59Mn, .044Nb, .001V, .028Al, .015Cu, .018Ni, .184Cr, .002Mo, .022Ti, 66ppm N, .019P, and .003S.
Current mech properties are: 630 MPA tensile, 515 MPA yield, 38% elongation.

By chall

Date 02-14-2006 13:10

X65 is considered an S1, Gr2 material in QW-422 of ASME Section IX. Based solely on that fact, we would treat it like we would treat a P1 material that did not require notch toughness.

From what you have stated I believe you should be able to do the PWHT without adversely affecting the mechanical properties.

Charles

By GRoberts (***)

Date 02-14-2006 15:00

From what I understand about most X-65, is that it is probably TMCP. PWHT can affect that material differently. Just wondering if anyone has experience PWHT X-65, and if so, what the results might have been. It looks like I'll probably end up having to simlate PWHT at several temperatures on some extra pieces, then test and see what we get.

By chall

Date 02-14-2006 16:29

http://www.intlsteel.com/PDFs/products/duracorravail.pdf

There is some interesting commentary about TMCP materials in that article. There is a reference made to ASTM A841, and some commentary about your question. Although A841 is not directly applicable to your situation, it is an informative read.

I have a copy of A841 and will send it if you need it (although it seems like you must have it already from your posting), just drop me an email.

Charles

By GRoberts (***)

Date 02-14-2006 17:41

Thanks for the link.

It actually looks like the pipe would conform to A841 Gr. F class 7 if it was plate. Interesting. Of course the brouchure only specifies that if PWHT is requried, that pretsting of the heat treating is recommended. Looks like that is where I was headed anyway.