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Forged RTJ flange with machined ring groove
3 August 2026

F91 RTJ Flanges Manufactured for a High-Temperature Power Plant Project

Project NewsPublished: 3 August 2026SASA FLANGE Project Team
Project completed

ASTM A182 F91 ring type joint flanges were manufactured for a high-temperature power plant piping package. The order combined controlled material condition with RTJ groove inspection, PMI, ultrasonic examination, hardness testing and documented dimensional release.

Project snapshot

Project status Manufacturing and final inspection completed
Material ASTM A182 F91 forged alloy steel
Flange type Weld neck RTJ
Standard ASME B16.5
Pressure class Class 900
Size range NPS 4–12; project-specific bores and weld ends
Inspection PMI, UT, hardness, RTJ groove and dimensional inspection
Application High-temperature power generation piping

Delivery highlights

RTJ groove geometry and surface condition were treated as critical sealing characteristics.
Hardness and heat-treatment records were reviewed alongside chemical identity.
Weld ends were matched to the project pipe wall and protected after inspection.

Why F91 required additional production control

F91 is a modified 9Cr-1Mo material whose high-temperature properties depend on the correct normalized-and-tempered condition. Chemistry alone cannot confirm that condition. The production route therefore preserved traceability to heat-treatment and mechanical-property records while preventing uncontrolled thermal exposure during later operations.

The flange hubs and weld ends were machined for the adjoining Grade 91 piping arrangement. Project welding and post-weld heat-treatment requirements remain part of the installed joint design and must be coordinated with the released flange condition.

RTJ groove and NDE verification

The ring groove was checked for profile, depth, pitch diameter, finish and freedom from damage. Ring number compatibility was verified from the approved project description. Ultrasonic testing addressed internal discontinuities in the forging, while visual and dimensional inspection covered accessible surfaces and geometry.

PMI, UT and hardness are complementary controls: PMI addresses alloy identity, UT addresses internal soundness and hardness supports verification of the delivered material condition.

Information needed for a comparable RFQ

A comparable inquiry should identify the exact material specification and grade, governing standard and edition, NPS, pressure class, flange type, facing, bore or matching pipe schedule, quantity and destination. For this project-news scope, the key reference points were ASTM A182 F91 forged alloy steel, Weld neck RTJ, Class 900 and NPS 4–12; project-specific bores and weld ends.

State the required EN 10204 certificate type, heat-number traceability, PMI extent, hardness limits, dimensional report, NDE method and acceptance standard, third-party witness points, packing method and required delivery date at quotation stage. Early definition allows manufacturing, inspection and document schedules to be reviewed together.

Production, inspection and packing photos

Images show the relevant SASA FLANGE production, quality-control and shipment stages used for this project-news report.

Long weld neck flange prepared for high-temperature piping
Forged hub geometry after controlled machining.
Ultrasonic testing of a forged piping component
UT examination supporting internal-quality verification.
Protected forged components in export packaging
Finished components packed for international transport.
ASTM A182 F91 Flanges for High-Temperature Piping Systems How to Match P91 Pipe with F91 Flanges NDT Inspection Methods for Forged Alloy Steel Flanges

Frequently asked questions

Can PMI prove that an F91 flange received the correct heat treatment?

No. PMI checks alloy chemistry. Heat-treatment records, mechanical properties and hardness provide evidence about material condition.

Why use an RTJ facing in high-pressure power piping?

RTJ joints use a metallic ring and machined groove for demanding pressure and temperature service when specified by the piping design.

Was the F91 flange selected independently of the pipe?

No. Grade, bore, weld end, filler metal and field heat-treatment planning must be reviewed as one piping system.

Request a quotation for alloy steel flanges

Send the ASTM grade, standard and edition, NPS, pressure class, flange type, facing, bore or pipe schedule, quantity, delivery destination and required PMI, NDE, hardness, third-party inspection and documentation.

Send Your RFQView Flange Products

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