1 1/4 Cr - 1/2Mo YIELD STRENGTH
1 1/4 Cr - 1/2Mo YIELD STRENGTH
(OP)
I am trying to design a TEMA BEM fixed tubesheet exchanger per ASME Sec. VIII, Div.1 with the following criteria:
Design Temp. = 1150°F
Metallurgy = 1 1/4Cr - 1/2Mo [plate (SA-387-11 Cls. 2), tubes (SA-213-T11), & Forgings (SA-182-F11 Cls 2)]
The problem I am running into is trying to interpret ASME Sec. II part D, Table Y-1. Although the material is allowed up to 1200°F, yield stresses are only listed up to 1000°F. However, I need the yield strength of the tubes, tubesheets, and shell cyl. at 1150°F to complete the UHX tubesheet calculations.
How can I find the values for yield strength at 1150°F? Does the code mention how to procede and if so where is it referenced?
Your help is greatly appreciated.
Design Temp. = 1150°F
Metallurgy = 1 1/4Cr - 1/2Mo [plate (SA-387-11 Cls. 2), tubes (SA-213-T11), & Forgings (SA-182-F11 Cls 2)]
The problem I am running into is trying to interpret ASME Sec. II part D, Table Y-1. Although the material is allowed up to 1200°F, yield stresses are only listed up to 1000°F. However, I need the yield strength of the tubes, tubesheets, and shell cyl. at 1150°F to complete the UHX tubesheet calculations.
How can I find the values for yield strength at 1150°F? Does the code mention how to procede and if so where is it referenced?
Your help is greatly appreciated.





RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
Regards,
Mike
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
Allowable stress around 1,900 at your design temperature? Save yourself and your customer some time and take a look at another material.
347/347H comes to mind.
-TJ Orlowski
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
Another teeny tiny point....
A TEMA BEM for 1100+ degrees F ???/? I don't think so....
TEMA BEM is good to a maximum of ~ 300F
Aside from your client's poor choice of materials, he has a very poor choice of HX design.
Ya, ya I know.....you are running out of time and you have to bid the spec.....your boss is an MBA...
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
From your reply it would appear that you have come across the same "numpties" out there with MBA's. It's a pity they have the ultimate say in decision making as they tend to get it wrong on the majority of times.
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
But anyhow, I remember seeing the fixed plate design dwgs for the clinch river liquid sodium HX ( never commissioned), and as I recall, the tubes were twisted, en masse, to allow some flexibility for thermal expansion, shell vs tubes, during transients. Exactly how is your design going to accomodate differential expansion during transients?
A beter design would be similar to "header type" heaters, with tubeside fluid distributed / accumulated in internal headers, and the tubes able to move slightly relative to each other , also add thermal sleeves at the header to shell connection. Tubing would be T23 or T91/92, but if T23 tubes are used, the tube stub at the header would need to be another alloy ( non bainitic) if teh heder wall thickness was greater than 1" .
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
Regards,
Mike
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
Its not all bad with MBAs. As a failure analyst I thank them daily for my job security.
RE: 1 1/4 Cr - 1/2Mo YIELD STRENGTH
careful now- it would be an MBA who would decide to outsource your job overseas.