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ASME B16.5 Lap Joint Flange (LJ)

American standard lap joint flange with lapped stub end. ASME B16.5. NPS 1/2"-24", Class 150-2500. Ideal for applications requiring frequent disassembly.

Lap Joint Flange (LJ)

The ASME B16.5 Lap Joint Flange (LJ) slides over a lapped stub end that is welded to the pipe. The flange itself is not welded to the pipe, allowing free rotation and easy removal without disturbing the pipe alignment. This makes lap joint flanges ideal for applications requiring frequent inspection, cleaning, or maintenance, such as tank farms, process plants, and food/beverage systems.

JIAJI FORGING manufactures Lap Joint flanges in austenitic stainless steel, duplex & super duplex stainless steel, and nickel alloys to ASME B16.5 standards. Stub ends are available as companion pieces.

Applications

  • Chemical and petrochemical plants
  • Food and beverage processing
  • Pharmaceutical industry
  • Paper and pulp mills
  • Tank farms and storage facilities
  • Cryogenic service

Pressure Ratings Available

  • Class 150 (PN20) / Class 300 (PN50)
  • Class 400 / Class 600 / Class 900
  • Class 1500 / Class 2500

Facing Types (ASME B16.5)

RF
Raised Face

FF
Flat Face

RTJ
Ring Joint

ASME B16.5 Lap Joint Flange (LJ)

Specifications

ParameterSpecification
StandardASME B16.5 (NPS 1/2"-24")
Size RangeNPS 1/2" - NPS 24" (DN15 - DN600)
Pressure RatingClass 150 / 300 / 400 / 600 / 900 / 1500 / 2500
Face FinishRaised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)
Materials304/304L (F8/F8A), 316/316L (F8/F8A), 321 (F8C), 347 (F8D), 310S, 904L, 2205 (F51), 2507 (F53), Inconel 625, Inconel 825, Hastelloy C276, Monel 400
Companion PartASME B16.9 Lap Joint Stub End (available)
SurfaceAnti-rust oil, black, galvanized, painted

Available Materials

Austenitic Stainless Steel

UNS / AISIASTM
304 / 304LA182 F8 / F8A
316 / 316LA182 F8 / F8A
321A182 F8C
347A182 F8D
310SA182 F310
904LA182 F904L

Duplex & Super Duplex

UNSASTM
S31803 (2205)A182 F51
S32205 (2205)A182 F51
S32750 (2507)A182 F53
S32760A182 F55

Nickel Alloys

UNS / AlloyASTM
N06625 (Inconel 625)A182 F65
N08825 (Incoloy 825)-
N10276 (Hastelloy C276)-
N04400 (Monel 400)-

Marking & Quality

Per ASME B16.5, each lap joint flange is permanently marked with: Manufacturer / Material / Pressure Class / Size / Face Type / Heat No.

Example: JIAJI · F316L · LJ · 4" · CL300 · RF · BATCH-2024

Stub ends (ASME B16.9) available as companion pieces. Optional: NACE MR0175, 3.1 / 3.2 inspection certificates (EN 10204), CE marking available upon request.

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