Overview
Pressure vessels — reactors, heat exchangers, separators, storage tanks, and columns — connect to the piping system through flanged nozzles. These flanges are governed by ASME Boiler & Pressure Vessel Code (BPVC) Section VIII, which imposes different design rules, material requirements, and inspection criteria than ASME B16.5 process piping flanges.
The key distinction: vessel flanges must be designed as integral parts of the vessel, accounting for shell stresses, nozzle loads (WRC 107/537), and the interaction between internal pressure and external piping forces. JIAJI FORGING manufactures vessel flanges with full BPVC compliance:
Appendix 2 flange calculation: gasket seating, bolt load, moment arms, and stress limits. UG-44 for standard flanges.
LWN flanges move the circumferential weld away from the high-stress nozzle-to-shell junction. Standard and custom hub lengths.
Non-standard bores, facing profiles, and bolt circles for unique vessel connections. Reverse engineering for replacement flanges.
Dissimilar metal welds between flange and vessel shell. Post-weld heat treatment requirements and buttering strategies.
Articles in This Cluster
ASME BPVC Section VIII Flange Design: UG-44 & Appendix 2
Flange design calculation per ASME BPVC Section VIII Division 1 Appendix 2. Gasket seating, bolt load, flange stress, and rigidity index.
Read Full Guide →Long Weld Neck (LWN) Nozzle Flanges: Design & Application
Extended-hub weld neck flanges for pressure vessel nozzles. Standard lengths (229mm/9"), custom lengths, and weld location advantages.
Read Full Guide →Custom Machined Flanges for Pressure Vessels
Non-standard bore sizes, special facing profiles, and custom bolt patterns. Design flexibility for unique vessel connections and retrofits.
Read Full Guide →Flange Face Protection for Vessel Nozzles
Protecting raised face and RTJ groove surfaces during vessel fabrication, transport, and erection. Cover types, materials, and inspection before bolting.
Read Full Guide →Material Selection for Pressure Vessel Flanges
Matching flange material to shell/head material per ASME BPVC Section II. Dissimilar metal welds (DMW), PWHT requirements, and impact testing.
Read Full Guide →Related Products
JIAJI FORGING manufactures the following forged products relevant to this topic:
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