Using SA/CSA G40.21 44W for Pressure Retaining Components

[Rmclach]

Good afternoon,

I am currently completing a design to ASME Section VIII, Division 1 2013 Edition. The vessel is 16" OD, 0.171" thick, 390 psi, 135F and service is propane. Our customer requires a custom fitting with female straight threads machined into the center for a temperature sensor. The diameter of the fitting is 1-3/8" OD X 2" long. The easiest way to do this is to use a round bar. However, SA-105, SA-181 and SA-516-70 do not come in round bar or it is not readily available. In Canada, CSA G40.21 38W/44W/50W is readily available for all steel shapes including round (nearly equivalent to SA-36).

UCS-6(b) states that you can use steel plates that conform to SA / CSA G40.21 38W in pressure parts in pressure vessels provided (1) through (3) are satisfied. Sub paragraph (3) states that the thickness of the plates on which strength welding is applied cannot exceed 5/8".

There is no mention that 44W or SA-36 can be used in bars or shapes for pressure containing components and I am of the opinion that this is not allowed in Sec VIII, Div. 1.

Is this correct? Clearly, we would like to use a round bar (44W/SA-36) versus the cost of using 2" SA-516-70.

Thank you,

Ryan

 

[marty007]

The 2013 edition of ASME includes SA / CSA G40.21 38W as well as 44W and 50W in both sections IID and VIII-1.

In IID, these materials are referenced as both plate and bar materials. As such, I would not be looking at UCS-6 for this application, but rather at UCS-12 which does not make such distinctions for the CSA G40.21 grades.

As long as you are getting bar grade rather than plate, I think you are okay.