Serrated Concentric & Spiral Flange Face Finish
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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Precision grooved surface texturing machined into raised face flanges with a 90° round-nosed tool to bite into soft gaskets and ensure high-pressure sealing.
Technical Explanation & Metallurgical Principles
A mirror-smooth flange face is counter-productive because high internal fluid pressure will blow the gasket outward. Standard ASME B16.5 specifications mandate a serrated gasket face finish between 125 and 250 microinches Ra (3.2 to 6.3 µm Ra) with 45 to 55 grooves per inch. The microscopic peaks bite into composite or graphite gaskets, holding them securely in place.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Roughness Range | 125 to 250 µin Ra (3.2 to 6.3 µm Ra) for standard sheet/spiral wound |
| Groove Geometry | Concentric or continuous spiral groove with 90° included angle |
| Groove Pitch | 45 to 55 serrations per inch (approx 0.5mm pitch) |
Application at Jayesh Forge (Rajkot Plant)
CNC-machined in Rajkot with precision digital feed rates on all raised face flanges up to 50 kg to guarantee leak-free seal performance.
Related Materials, Standards & Products
Applicable Material Grades
Related Metallurgical & Testing Terms
Raised Face (RF Flange Facing)
A raised annular gasket sealing surface elevated 1/16" (1.6mm) or 1/4" (6.4mm) above the flange bolt hole circle.
Flange Facing Serrated Finish (Serrated Spiral / Concentric)
The standardized micro-groove surface finish machined onto the raised face of a flange to bite into sheet or spiral-wound gaskets under bolt compression.
ASME B16.5 Pipe Flanges Standard
The definitive American standard covering pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges NPS 1/2 through NPS 24.
Questions Regarding Serrated Concentric & Spiral Flange Face Finish
Concentric serrations are specified for low-density fluids and toxic gases like hydrogen or chlorine where a spiral groove could provide a continuous leak path along the groove spiral.
Request a Forging Quote with Serrated Concentric & Spiral Flange Face Finish Compliance
Our Rajkot metallurgy desk is ready to review your technical drawings, testing protocols, and delivery schedules for custom closed-die forgings strictly up to 50 kg.