หน้าแปลน RF และ RTJ สำหรับการใช้งานที่มีแรงดันสูง

Technical NewsReviewed: 3 สิงหาคม 2026By SASA FLANGE Technical Content Team

Direct answer

RF flanges seal by compressing a gasket against two raised faces. RTJ flanges seal by deforming a metallic ring gasket inside matched grooves. RTJ is commonly selected for severe high-pressure or high-temperature services when the line class and mating equipment require it, but it is not automatically better for every application. Facing, gasket, class and mating geometry must match exactly.

Key takeaways

RF and RTJ describe different sealing systems, not cosmetic face options.
An RTJ joint requires two compatible grooves and the specified metal ring.
High pressure alone does not decide the facing; the line class and service do.

How RF and RTJ sealing differ

Feature	เงยหน้าขึ้น (รฟ)	Ring-Type Joint (RTJ)
Sealing element	Compressed gasket on raised surfaces	Metal ring gasket seated in matched grooves
Contact pattern	Broader gasket contact area	Concentrated metal-to-metal ring contact
Common use	Wide range of process and utility duties	Severe pressure/temperature duties defined by line class
Critical inspection area	Face flatness, finish and damage	Groove profile, เสร็จ, corrosion and mechanical damage

Both designs can provide reliable service when correctly specified, machined, assembled and maintained. Neither facing compensates for inadequate bolting, misalignment or uncontrolled external loads.

When RTJ is commonly specified

RTJ connections are often found in higher-pressure refinery, ปิโตรเคมี, offshore and oil-and-gas systems. The metal ring and groove arrangement can suit demanding joint requirements, but selection must follow the project line class and the available facing provisions for the selected standard and class.

Installation quality is critical. The ring material and profile must be correct, grooves must be clean and undamaged, and the flanges must be aligned. A reused or incorrect ring can compromise the seal even when the flange material and class are correct.

Compatibility and conversion traps

An RF flange should not be bolted to an RTJ flange as a normal field solution. The facing geometry and sealing concept differ. Converting a joint requires engineering approval, compatible replacement components and verification of dimensions, rating, gasket, bolting and connected equipment.

Buyers should state the exact facing and any groove designation required by the project. “RTJ flange” by itself may still omit the standard, กรมอุทยานฯ, ระดับ, วัสดุ, ประเภทหน้าแปลน, groove or ring reference, bore and finish.

Inspection and ordering checklist

ASME standard, กรมอุทยานฯ, class and flange type
RF or RTJ facing and required finish
RTJ groove and ring-gasket designation where applicable
ASTM material specification and exact grade
Mating-flange or equipment-nozzle details
Face or groove dimensional inspection
Protection against corrosion and handling damage
Bolting, gasket, เอ็มทีซี, ข้อกำหนด PMI และ NDE

Keep machined faces protected through shipping and storage. Damage in an RTJ groove or across an RF sealing path can be more consequential than rust on a non-sealing exterior surface.

คำถามที่พบบ่อย

Is RTJ always better than RF at high pressure?

เลขที่. RTJ is common in severe service, but the approved standard, ระดับ, line class, gasket strategy and mating equipment determine the correct facing.

Can an RF flange mate with an RTJ flange?

They are not a normal compatible pair. Any conversion requires engineered replacement or an approved joint solution.

Can an RTJ ring gasket be reused?

Metal rings are generally treated as single-use sealing elements unless the governing procedure explicitly permits otherwise.

Primary standards referenced

Standards were checked against publisher pages on 3 สิงหาคม 2026. Always purchase and apply the edition specified by the project.

Request an alloy steel flange quotation

Send the material grade, มาตรฐาน, กรมอุทยานฯ, ระดับความดัน, ประเภทหน้าแปลน, หันหน้าไปทาง, pipe schedule, ข้อกำหนดด้านปริมาณและการตรวจสอบ. Our team will review the technical description before quotation.

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