Impact test exemption for SS materials

[H Cameron]

Hi guys,

As UG is general requirements for all material in ASME Section VIII, is it required to address para. UG-20(f) for a vessel which completely made from SS? We have already addressed to UHA-51. But the inspector doesn’t accept that.

Thanks

 

[SnTMan]

Doesn't sound like the inspector has actually read UG-20(f).

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[H Cameron]

UG-20(f) is referred to UG-84, and in UG-84 there are some para about UHA.

The inspector may be correct.

What’s your idea?

 

[metengr]

UG-20 (f) applies to a specific exemption for impact testing of PV materials under design metal temperature. Stainless steel in this case would not be exempted by UG-20(f) and defaults to requirements in UG-84.

 

[H Cameron]

Is there any specific part of UG-20 shows we cannot use this part as a reference for UHA exception?

Thanks

 

[metengr]

First here is an excerpt

(f) Impact testing per UG-84 is not mandatory for pressure
vessel materials that satisfy all of the following:

(1) The material shall be limited to P‐No. 1, Gr. No. 1
or 2, and the thickness, as defined in UCS-66(a) [see also
Note (1) in Figure UCS-66.2], shall not exceed that given
in (-a) or (-b) below:
(-a) 1/2 in. (13 mm) for materials listed in Curve A
of Figure UCS-66;
(-b) 1 in. (25 mm) for materials listed in Curve B,
C, or D of Figure UCS-66.
(2) The completed vessel shall be hydrostatically
tested per UG-99(b) or UG-99(c) or 27-4. Alternatively,
the completed vessel may be pneumatically tested in accordance
with 35-6.
(3) Design temperature is no warmer than 650°F
(345°C) nor colder than −20°F (−29°C). Occasional operating
temperatures colder than −20°F (−29°C) are acceptable
when due to lower seasonal atmospheric
temperature.
(4) The thermal or mechanical shock loadings are not
a controlling design requirement. (See UG-22.)
(5) Cyclical loading is not a controlling design requirement.
(See UG-22.)


So, all of the items above 1-5 must be met for the exemption. Since there is no mention of UHA steels, you go to UG-84 and follow from there.

 

[H Cameron]

metengr

Thanks.

so do you agree with the inspector about addressing to UG?