Haihao Group Supplies API 17D Swivel Flange with Cladding for Singapore Offshore Replacement Project

As part of an offshore equipment replacement program in Singapore, Haihao Group has successfully completed the production and shipment of a 7 1/16″ API 17D Type 17SV swivel flange assembly. The component, supplied under TAG No. ESP-12101958, includes a swivel flange, positioning ring, and corrosion-resistant weld overlay, engineered for 10,000-psi service in critical subsea operations.

This project required a combination of super duplex stainless steel UNS S32760 and Inconel 625 overlay, along with full compliance to NACE MR0175, ABS cladding qualification, and multiple mechanical and corrosion-resistance tests.

Product Scope and Technical Requirements

Supplied Item

• Product: Swivel flange + positioning ring + weld overlay

• Size: 7 1/16 inch

• Pressure rating: 10,000 psi

• Seal face type: RTJ BX-156

• Standard: API 17D Type 17SV

• Base material: ASTM A182 F55 / UNS S32760

• Overlay material: Inconel 625

• TAG NO.: ESP-12101958

• Hab dimension: 102.79

• Ring dimension: 87.5

The component was produced with strict heat treatment requirements and protective measures for the sealing surface and hub-including custom end caps to prevent contamination or handling damage during transport.

Compliance With Offshore and Sour-Service Requirements

To ensure reliability in harsh subsea environments, the swivel flange assembly was manufactured in accordance with the full suite of sour-service and corrosion-control standards:

NACE MR0175 Compliance

The UNS S32760 forging and Inconel 625 overlay fully meet hydrogen-sulfide service requirements, ensuring long-term resistance to stress-corrosion cracking.

ABS-Approved Cladding Procedure

The customer required ABS endorsement of the welding procedure specification (WPS).
Each PQR included:

• Base material certificates

• Filler metal certificates

• PWHT records

• Non-destructive examination reports

• Mechanical-testing results

• Laboratory testing documentation

• Weld-overlay qualification samples (made with furnace test coupons)

Enhanced Inspection and Testing Program

To guarantee performance under offshore pressure-control equipment conditions, Haihao Group implemented a comprehensive inspection plan:

Material and Corrosion Tests

• PMI with PREN verification ≥ 37.7 (target 40)

• Pitting corrosion test: ASTM G48 Method A

• Ferrite content: 35%–55%

• Hardness: ≤ 32 HRC

Non-Destructive Testing

• 100% ultrasonic testing after rough machining

• Penetrant testing upon completion of final machining

Mechanical Testing

• Tensile and yield strength tests

• Charpy impact test at –50°C (average ≥45 J, minimum 35 J)

These inspections ensure the component maintains stability, mechanical integrity, and corrosion resistance in offshore drilling and subsea control applications.