Dear Patel;
Your Question with description of the flange:
You are going to purchase a SA 266 Gr.4 WNRF flange, which is designed as per Appendix 2 of ASME Sec VIII Div.1, the query is does this forging needs to meet the ordering requirement of SA266 Gr.4 specification which calls for, hubbed flanges needs to be tensile tested as per SA 788 specification. Does this requirement is mandatory even if it is supplied as forged WNRF flanges
Supporting Section II Part A Information for SA-266 and A-788 specifications:
SA-266 Grade 4 SPECIFICATION FOR CARBON STEEL FORGINGS FOR PRESSURE VESSEL COMPONENTS
3. Ordering Information and General Requirements
3.4 For hubbed flanges and tube sheets ordered for ASME Boiler and Pressure Vessel Code application, Supplementary Requirement S12 of Specification A 788 shall be specified in addition to Supplementary Requirement S8 of this specification.
S8. Specimen Location on Forged Hubs
S8.1 Forged hubs to be butt-welded to shells shall be:
forged in such a manner as to provide in the hub the full minimum tensile strength and elongation specified for the material, in a direction parallel to the axis of the vessel. A tension specimen (subsize if necessary) shall be taken in this direction and as close to the finished hub outside diameter as practical.
SA-788 SPECIFICATION FOR STEEL FORGINGS, GENERAL REQUIREMENTS
S12. Tension Specimens for Hubbed Flanges and Tube Sheets
S12.1 For hubbed tube sheets and flanges to be used in ASME Boiler and Pressure Vessel Code construction, an axial tension specimen shall be taken as close as possible to the hub and either inboard or outboard of it, using a sub size specimen if necessary. The longitudinal axis of the specimen shall be parallel to the length of the hub, as shown in Fig. S 1.
S12.2 By agreement with the purchaser, this test orientation
may replace a specified tension test specimen, provided
that other location criteria are met.
Supporting information from Section VIII, Div. 1 Appendix 2:
Figure 2-4 Sketch 6 Illustrates a weld neck raised face (WNRF) flange.
The three sketches in Fig. 2-4 Sketches 6, 6a, and 6b locate the dimensions "h", "g1" and"go" which are defined in 2-3 Notation as follows:
The term "h" denotes hub length,"go" denotes thickness of hub at small end and "g1"denotes thickness of hub at back of flange.
The final determination that this is a hub flange is the value of ""h" used in the flange calculations. Should any value of "h" be used which is larger than zero (0.0) the calculation will have taken credit for the hub.
The flanges shown in Fig. 2-4 Sketches 6, 6a, 6b and 7 are integral hub flanges and are calculated as such.
It is my opinion that your question may be answered as follows:
Reply: The flange described in your question is a hub flange as defined in ASME Section VIII, Div. 1 Appendix 2, designed using a value of "h" larger than zero.
Specification SA-266 calls in Specification A-788 and establishes the supplemental requirement S12 to be part of the specification requirements.
Based on this the tensile tests stated in S12 of A-788 are mandatory requirements for the described flange.
S12.1 For hubbed tube sheets and flanges to be used in ASME Boiler and Pressure Vessel Code construction, an axial tension specimen shall be taken as close as possible to the hub and either inboard or outboard of it, using a sub size specimen if necessary. The longitudinal axis of the specimen shall be parallel to the length of the hub, as shown in Fig. S 1.
S12.2 By agreement with the purchaser, this test orientation
may replace a specified tension test specimen, provided
that other location criteria are met.
Supporting information from Section VIII, Div. 1 Appendix 2:
Figure 2-4 Sketch 6 Illustrates a weld neck raised face (WNRF) flange.
The three sketches in Fig. 2-4 Sketches 6, 6a, and 6b locate the dimensions "h", "g1" and"go" which are defined in 2-3 Notation as follows:
The term "h" denotes hub length,"go" denotes thickness of hub at small end and "g1"denotes thickness of hub at back of flange.
The final determination that this is a hub flange is the value of ""h" used in the flange calculations. Should any value of "h" be used which is larger than zero (0.0) the calculation will have taken credit for the hub.
The flanges shown in Fig. 2-4 Sketches 6, 6a, 6b and 7 are integral hub flanges and are calculated as such.
It is my opinion that your question may be answered as follows:
Reply: The flange described in your question is a hub flange as defined in ASME Section VIII, Div. 1 Appendix 2, designed using a value of "h" larger than zero.
Specification SA-266 calls in Specification A-788 and establishes the supplemental requirement S12 to be part of the specification requirements.
Based on this the tensile tests stated in S12 of A-788 are mandatory requirements for the described flange.
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