Dear All

We are manufacturing heat exchanger , For HE impact test is required at -46.

We are using tubes of SA179 .

Im not found any where impact test required for these tubes in ASME Sec II part A . Any one can advise these tubes are impact tested at -46 when we using in same exchanger . Or it is not required .

tube wall thickness is 2.11 mm .
Inthu

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BE DARE
A positive a itude

Dear Inthu,

I feced in the past a similar "problem" which has been solved in this way:

1) with 25.4 or 19.05 tube OD and thk 2.11 mm it is not possible to obtain a speciments from the tubes due to the dimension of speciment (refer to UCS-66) even if the speciment dimensions are reduced....
I do not remember the paragraph about this......

2) we changed the tubes material from SA 179 to SA 334 Gr.6.
SA 334 gr.6 material is suitable for cold temperatures such as -45°C.
The SA 334 gr.6 price is very close to that of SA 179 ( sometimes I got the same price...)

3) since I do not remember the allowable stresses, please check and compare the alllowable stresses and assure that the SA 334 Gr.6 is still OK for your design conditions...

4) Be sure that the Design Code is ASME VIII Div.1 since if I remember well the SA 334 Gr.6 material is not admitted for Div.2.


If all the conditions are OK so you can propose to your Client the SA 334 Gr.6 with NO need to impact tested the tubes (i.e. Impact test is not required)......

In my personal opinion and for my experience this is well accepted proposal.

Hope this could help you....

Let me know about ...

GENGI

Inthu,

Your 2.11 mm thick SA-179 tube is exempt from impact testing, but it should not be used at an MDMT that is colder than -48 deg. C. Refer to UCS-66(d).

_________________
BE DARE
A positive a itude