Governing Thickness of Non-Standard Flanges for Impact Testing

[ashaykadam]

I observed a conflict in two clauses of ASME Sec. VIII Div. 1 UCS-66 as follows:

UCS-66 (a)(3): The governing thickness of nonwelded parts, such as bolted flanges, tubesheets and flat heads, is the flat component thickness divided by 4.

FIG. UCS-66.3 (c): tg2 = tc;
where, tc = thickness of shell welded to flange.
Flange thickness is not considered.

What thickness shall be considered while checking Impact Test requirement for a Non-Standard Flange?
- Flange Thickness/4; as per UCS-66 (a)(3) or
- Thickness of shell welded to flange; as per FIG. UCS-66.3 (c)

I feel in case of FIG. UCS-66.3 (c), they have forgotten to specify note that," The governing thickness of 'A'; means Bolted Flat Cover, is the greater of tg1 & tg2. (which appears in Fig. (d) & (c))
In that case this FIG. UCS-66.3 (c) will be applicable only for determination of govering thickness of 'Bolted Flat Cover' & shall not be used for Flange by any means.

Please provide your opinion.

Thanks.

Ashay Kadam
Manager
Mechanical Department

Uhde India Private Limited
Mumbai, India.

 

[SnTMan]

ashaykadam, see UCS-66(a), 2nd para. for separate components.

Butt welded? See UCS-66 (a)(1)(a).
Corner joint? see UCS-66(a)(1)(b).
Not welded to another piece? See UCS-66(a)(1)(c).

Regards,

Mike

 

[dineshakabari]

In my opinion, in case of non welded parts only T/4 to be considered. But if it is welded then welded thickness criteria needs to be considered. (maximum of T/4 and tw).