Blind Flange

Description

Blind flanges serve as essential pressure boundary components in piping and pressure vessel systems, providing secure closure of pipe ends, vessel openings, and future connection points. Manufactured as solid discs with precision-drilled bolt circles, these critical components are engineered to withstand full system pressure while facilitating maintenance, testing, and system expansion capabilities.

Technical Specifications:

Material Composition:

• Carbon Steel: ASTM A105 (Standard Forged), A350 LF2 (Low Temperature), A694 F52/F60/F65 (High Yield)

• Stainless Steel: ASTM A182 F304/304L, F316/316L, F321, F347, Duplex 2205/2507

• Alloy Steel: ASTM A182 F11 (1¼Cr-½Mo), F22 (2¼Cr-1Mo), F91 (9Cr-1Mo-V)

• Special Alloys: Monel 400/K500, Inconel 600/625, Hastelloy C276, Titanium Gr.2

Design Standards & Classifications:

• Dimensional Standards: ASME B16.5 (1/2″-24″), ASME B16.47 Series A/B (26″-60″)

• Pressure Classes: 150#, 300#, 600#, 900#, 1500#, 2500#

• PN Ratings: PN6, PN10, PN16, PN25, PN40, PN63, PN100, PN160, PN250

• Facing Types: Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)

• Surface Finish: 125-250 µin Ra (Serrated), 63-125 µin Ra (Smooth)

Manufacturing Processes:

• Forging: Closed-die forging for optimal grain structure

• Plate Cutting: CNC plasma/oxy-fuel from certified plate material

• Machining: CNC turning and drilling for dimensional accuracy

• Heat Treatment: Normalizing, quenching & tempering as required by specification

• Testing: Non-destructive examination per applicable codes

Key Dimensions & Tolerances:

• Thickness: Per ASME B16.5 Table 7 (minimum thickness requirements)

• Bolt Circle: ±0.06″ tolerance on bolt hole diameter

• Bolt Holes: Diameter per ASME B16.5 Table 11

• Facing: Flatness within 0.015″ across any diameter

Performance Characteristics:

• Pressure Rating: Full pressure rating of matching flange class

• Temperature Range: -320°F to +1200°F depending on material grade

• Corrosion Allowance: Standard 1/16″ (1.5mm) or as specified

• Sealing Capability: Designed for zero-leakage performance

Quality Assurance Protocol:

• Material Certification: Full MTR with chemical analysis and mechanical properties

• Dimensional Verification: 100% inspection to drawing requirements

• Surface Inspection: Visual per MSS SP-55 standards

• NDT Requirements: UT/MT/PT as specified by order

• Marking: Clear stamping per ASME B16.5 requirements