Flange Facing Serrated Finish (Serrated Spiral / Concentric)
Engineering definition, metallurgical mechanisms, standard testing specifications, and manufacturing guidelines for closed-die forgings up to 50 kg.
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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.
Technical Explanation & Metallurgical Principles
Per ASME B16.5, raised face and large flat face flanges require a serrated concentric or serrated spiral (phonographic) grooved finish with an average surface roughness between 125 µin and 250 µin (3.2 µm to 6.3 µm Ra). The 45° to 55° grooves provide mechanical anchoring that prevents gasket blowout under high internal line pressure.
Key Engineering Specifications & Parameters
| Technical Parameter / Metric | Engineering Benchmark / Value |
|---|---|
| Standard Roughness | 125 µin to 250 µin Ra (3.2 µm to 6.3 µm) |
| Groove Density | 45 to 55 grooves per inch (approx 0.5mm pitch) |
| Tool Radius | 1.6mm (0.06 in) round-nosed cutting tool |
Application at Jayesh Forge (Rajkot Plant)
Precision-machined on computer-controlled CNC lathes in Rajkot with surface roughness verified using calibrated stylus profilometers.
Related Materials, Standards & Products
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.
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.
Ring Type Joint (RTJ Flange Facing)
A specialized flange facing featuring a precision-machined trapezoidal ring groove engineered to seat an octagonal or oval solid metallic ring gasket.
Questions Regarding Flange Facing Serrated Finish (Serrated Spiral / Concentric)
A mirror-smooth finish would allow soft or spiral-wound gaskets to extrude outward under high bolt preloads; serrations mechanically lock the gasket in place.
Request a Forging Quote with Flange Facing Serrated Finish (Serrated Spiral / Concentric) 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.