Haihao Group Supplies ASME B16.5 F316/316L Weld Neck Flange for Sour Service
Haihao Group has completed an order of ASME B16.5 F316/316L weld neck flanges for a customer in Singapore. The shipment consists of 1/2-inch Class 150 RF weld neck flanges manufactured from SA/A182 F316/316L, with SCH 40S thickness and requirements for sour service.
Although the flange size is small, the specification includes several important inspection and material requirements. The order calls for 100% liquid penetrant examination (LPE), 100% positive material identification (PMI), reporting of actual Cr, Ni, Mo and C contents, and compliance with NACE MR0175/ISO 15156 requirements.
Product Details
The supplied flange is a 1/2-inch Class 150 RF weld neck flange designed in accordance with ASME B16.5. The raised-face configuration provides the specified sealing surface for connection with the mating flange and gasket.
| Product | Size | Wall Thickness | Pressure Class | Facing | Material | Standard |
| Weld Neck Flange RF | 1/2″ | SCH 40S | 150# | RF | SA/A182 F316/316L | ASME B16.5 |
The combination of F316/316L stainless steel, Class 150 pressure rating and raised-face design provides a compact flange solution for process piping where corrosion resistance and material verification are important.
ASME B16.5 F316 316L weld neck flange for sour service manufactured by Haihao Group
F316/316L Material for Sour Service Applications
The flange material is specified as SA/A182 F316/316L. This dual-grade specification combines the requirements of F316 and F316L stainless steel, while the purchase specification adds sour-service requirements.
For this order, material verification goes beyond simply identifying the grade on the material certificate. Haihao Group is required to perform 100% PMI and provide a report of the actual measured elemental contents of chromium (Cr), nickel (Ni), molybdenum (Mo) and carbon (C).
This provides the customer with direct chemical composition data for the supplied ASME B16.5 F316/316L weld neck flange.
The purchase specification also notes that carbon testing is required when specifically indicated on the data sheet or purchase document. It may also be requested when applicable code stress values require a minimum carbon content for high-temperature service.
Inspection Requirements for the Singapore Order
Inspection requirements are an important part of this shipment. The customer specified:
100% Liquid Penetrant Examination (LPE)
100% Positive Material Identification (PMI)
PMI report with actual measured Cr, Ni, Mo and C contents
Sour-service requirements according to NACE MR0175/ISO 15156
SA/A182 F316/316L material
ASME B16.5 dimensional and pressure-class requirements
For stainless steel flanges used in demanding process environments, PMI provides an additional layer of material verification. Instead of relying only on heat-number identification and documentation, PMI checks the chemical composition of the finished component.
For this ASME B16.5 F316/316L weld neck flange order, the reporting requirement is particularly relevant because the customer requested actual measured elemental values rather than only a standard material designation.
Why Weld Neck Flanges Are Used
A weld neck flange is connected to the pipe through a butt weld. Its long tapered hub provides a gradual transition from the flange body to the pipe, making this flange type commonly selected for process piping applications where welded connections and controlled stress distribution are required.
The RF, or raised-face, configuration provides a defined gasket seating surface. For a Class 150 connection, the flange dimensions, bolt-hole arrangement and pressure-class requirements are governed by the specified ASME B16.5 standard.
When selecting an ASME B16.5 F316/316L weld neck flange, buyers should therefore consider more than nominal size. Material grade, schedule, pressure class, facing, service conditions and inspection requirements all need to match the project specification.
Sour-Service Compliance and Documentation
The Singapore order was specified for sour service, with NACE MR0175/ISO 15156 requirements included in the purchase specification.
Sour-service applications require careful control of material selection and inspection because the operating environment can impose additional requirements on metallic components. For this reason, the manufacturing documentation for the order is aligned with the customer’s specified material and inspection requirements.
Haihao Group pays particular attention to the consistency between the purchase specification, material identification, inspection records and final product marking. This helps customers maintain traceability throughout their procurement and quality-control process.
Looking for stainless steel weld neck flanges for sour-service piping? Contact Haihao Group with your size, pressure class, material and inspection requirements for a project-specific quotation.