Lap Joint Flange — Technical Data Sheet

Specification

Materials

Typical applications

• Stainless and alloy piping where a carbon steel backing flange saves cost
• Lines that are dismantled often for cleaning or inspection
• Where bolt-hole alignment is difficult

Manufacturing

• Raw material: forging-quality billets or bars from approved mills, verified by chemical analysis and PMI on alloy and stainless grades.
• Forming: closed-die or open-die forging, followed by rough machining.
• Heat treatment: normalising, normalising and tempering, quench and temper, or solution annealing as the material specification requires, with recorded furnace charts.
• Machining: CNC turning and drilling to ASME B16.5 / B16.47 dimensions and tolerances.
• Facing finish: serrated spiral or concentric finish of 3.2–6.3 µm Ra (125–250 µin) on raised and flat faces; 1.6 µm Ra (63 µin) maximum on ring-joint groove side walls.

Inspection and testing

• Chemical analysis and mechanical tests (tensile, hardness; Charpy impact for low-temperature grades) per heat and heat-treatment lot.
• 100% visual and dimensional inspection against ASME B16.5 / B16.47.
• Ultrasonic, magnetic-particle or dye-penetrant examination when specified.
• Positive material identification (PMI) on stainless and alloy steel.
• Intergranular corrosion test to ASTM A262 Practice E for stainless grades when specified.
• Third-party inspection at our works as required by the order.

Marking

Hard-stamped on the rim to ASME B16.5 / MSS SP-25: manufacturer's mark, size, class, facing, bore / schedule, material grade, heat number and standard.

Documentation

Mill test certificate to EN 10204 3.1 (3.2 with third-party inspection on request), dimensional inspection report, heat-treatment record where applicable, and NDT reports as specified. IBR certification on request.

Packing

Rust-preventive coating on machined surfaces, plastic end / face protectors, and seaworthy wooden cases or pallets marked with PO line, size, heat number and quantity.

Ordering information

Please state the following on your enquiry:

• Type, nominal size (NPS) and pressure class
• Facing: raised face (RF), flat face (FF) or ring type joint (RTJ)
• Bore or pipe schedule (weld neck, socket weld and lap joint)
• Material specification and grade
• Standard: ASME B16.5 or ASME B16.47 Series A / B
• Supplementary requirements: NDT, impact test temperature, NACE MR0175, IBR, third-party inspection
• Quantity and delivery point

Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.

Dimensions