ASME B31.3 CHPT IX API 5L X60

[17092003]

Hi all,

Hopefully someone can assist me here.

I've got an application where API 5L X60 material has been preliminarly chosen for a high pressure (500Barg) piping system in a B31.3 CHPT IX design code. As the design temperature is up to 90°C, allowable stress needs to be determine at this design temperature for pipe WT cals from OD 2" to OD 6" (pipe will be SMLS). At ambient table K1 states 40ksi, thus to determine bases for allowable ratio Ry is stated in K302.3.2. How is this Ry ratio applied to determine allowable stress at 90°C?

I know ASME II part D doesn't include API 5L grades.

Thanks.

 

[metengr]

I believe you did not read all of the applicable notes in Table K-1. Since API 5L X60 is listed in Table K-1 it shows no allowable stress values above 100 deg F, Why? Because read Note 21 below;

At temperatures above 100°F, the allowable stresses listed in
Table A-1 for this material may be used for Chapter IX applications.
Alternatively, allowable stresses may be derived in
accordance with the requirements of para. K323.2.1.

 

[stanweld]

Table K-1, Note (21), quoted above, clearly permits the use of seamless {Note (8)} API 5LX-60 pipe using the allowable stresses in Table A-1 to a maximum temperature of 400F for Chapter IX applications. Welding procedures must be qualified on X60 pipe per Note (10).

 

[stanweld]

Finally, K323.2.1 references paragraph 302.2.2, not K302.2.2.

 

[17092003]

Thanks metengr, but note 21 has been previously understood, which references table A1 states 25ksi allowable stress constant from 37.7°C to 204°C, which is considerably lower than table K1 40ksi at 37.7°C. Based on table A1 allowable stress WTs are lower.

Note 21 refers back to K323.2.1 (b) to K323.2.4 (a) and (b). Reviewing K323.2.4 (b) takes me to K302.3.2, thus the R ratio. Any guidance for this R ratio in this instance?

Thanks Stanweld, but WTs are lower using table A1 in comparison to table K1 for X60.

 

[stanweld]

You have discovered the truth. The permitted design allowables are lower; the wall thicknesses are greater under Table A-1. You may only use the high design allowable per Table K-1 at or below 100F.