A/SA 691 P91 Welded Vs A335 P91
A/SA 691 P91 Welded Vs A335 P91
(OP)
A number of years back I worked with a domestic E&C getting A/SA 691 P91 pipe approved for use in Power Plant construction. After months of testing and qualification in Europe, the welded pipe was finally approved. I am trying to understand the current B31.1 and Section 1 requirements related to the use of welded construction (Pipe) in power (boiler) applications. Specifically, where can welded be utilized AND where does the code still mandate a seamless product.
thanks for the input on this topic.
thanks for the input on this topic.





RE: A/SA 691 P91 Welded Vs A335 P91
ASME B31.1 does permit use of A 691 pipe material (see Mandatory Appendix A, Table A-2.
RE: A/SA 691 P91 Welded Vs A335 P91
Also, if the pipe is being seam welded by a mon + pop forge, make sure they cool the pipe from the 1900 F normalizing temp fast enough to prevent ferrite formation.