Material high conditions
Material high conditions
(OP)
Hi All,
I have designing a piping system in very high conditions. It´s a based water fluid and the conditions 350 bar (5076 psi) and 760ºC (1400 F). I am thinking in pipe B444 Alloy 625 (UNS N06625). The pipes that I need are 3/4", 1" and 1 1/2", but the thicknness obtained in the calculation are very high (I have to select Sch.XXS and we have many problems to find suppliers of this pipe).
What do think about that?
Do you recomended another material?
Thanks in advance.
I have designing a piping system in very high conditions. It´s a based water fluid and the conditions 350 bar (5076 psi) and 760ºC (1400 F). I am thinking in pipe B444 Alloy 625 (UNS N06625). The pipes that I need are 3/4", 1" and 1 1/2", but the thicknness obtained in the calculation are very high (I have to select Sch.XXS and we have many problems to find suppliers of this pipe).
What do think about that?
Do you recomended another material?
Thanks in advance.





RE: Material high conditions
What piping design code are you using for this high pressure and temperature system???
RE: Material high conditions
I am using B31.3
Do you recomemded another one?
RE: Material high conditions
The design code is fine. At this service temeprature you will be limited in material selection to Ni-based alloys and wall thickness based on allowable stresses.
RE: Material high conditions
RE: Material high conditions
So, do you think that Alloy 625 is not valid for this temperature?
RE: Material high conditions
Thank you for your information. I am searching the values of the "Basic Allowable Stresses" (S) in B31.3 tables for Alloy 617=N06617 and Alloy 718=N07718, but I don´t find it. Where I can find this data (at the temperature) to use in B31.3 calculation?
Thanks.
RE: Material high conditions
You have two options for using material not listed in Appendix A of B31.3. You can determine alowable stress by testing and methodes stated in B31.3 or you can use material listed in ASME B&PV Code, Section II, Part D. I would recommend you stick with material in Appendix A of B31.3.
RE: Material high conditions
If I use the values from ASME Sec. II PART D, Have I to apply some factor of safety? or I can use the listed values?
Thanks.
RE: Material high conditions
You can use the listed values in Section II Part D provided they are as conservative as B31.3 values in Appendix A. This is why I would remain with B31.3 endorsed materials.
RE: Material high conditions
You might want to look into Haynes 230 (UNS N06230). It might be covered by a code case (#2063) still rather than being in the tables, but has very high design stresses at 1400F and you would have a reasonable chance of getting pipe in it.