ASTM A105N WN Flange for Iraq Project: 1″ Class 150 RF, SCH 160

Haihao Group recently completed the supply of a 1-inch ASTM A105N weld neck flange for an Iraqi customer. The order was specified for Class 150 service, raised face (RF), Schedule 160, and compliance with ASME B16.5 and NACE MR0175.

This order is a good example of a small-diameter flange with a demanding wall-thickness requirement. Instead of using a general-purpose configuration, the flange was manufactured according to the specified pipe schedule and project requirements.

ASTM A105N weld neck flanges Class 150 RF SCH 160 ASME B16.5

1-Inch ASTM A105N Weld Neck Flange

The supplied product is a weld neck (WN) flange with a raised face. Weld neck flanges are commonly selected where the connection requires a butt-welded transition between the flange and pipe. ASME B16.5 covers dimensional and pressure-temperature requirements for pipe flanges and flanged fittings within its applicable size range.

For this Iraqi order, the key specifications were:

The combination of ASTM A105N, Class 150, SCH 160 and ASME B16.5 requires attention to the flange bore, welding end and sealing face during machining. ASTM A105 covers forged carbon steel piping components used in pressure systems, including flanges and fittings.

Why SCH 160 Matters

Although the pressure class is 150 LB, the connected pipe has a Schedule 160 wall thickness. Therefore, the flange bore needs to be produced to suit the specified pipe connection rather than treated as a standard thin-wall configuration.

For a 1-inch Class 150 weld neck flange, ASME B16.5 dimensional references include the flange outside diameter, bore, thickness, bolt arrangement and overall length.

This is where production control becomes important. The ASTM A105N WN flange must not only meet the material requirement but also maintain the specified machining dimensions and raised-face condition.

NACE MR0175 Requirement

The order also specified NACE MR0175, indicating that the flange was required to meet the customer’s specified sour-service requirements.

For oil and gas projects, material selection and manufacturing controls are particularly important when components may be exposed to sour environments. Haihao Group follows the customer’s material, dimensional, inspection and documentation requirements when manufacturing flanges for such applications.

Haihao Group’s Approach to Custom Flange Orders

Small-size flanges can still require precise manufacturing when the specification combines multiple requirements. For this order, the main control points included:

• 1-inch nominal size
• Class 150 pressure rating
• Schedule 160 connection
• Raised Face (RF)
• ASTM A105N carbon steel
• ASME B16.5 dimensional requirements
• NACE MR0175 requirement

Haihao Group supplies forged flanges for oil & gas, petrochemical, power and other industrial pipeline applications. ASTM A105-type forged carbon steel components are specifically used for pressure-system piping applications.

If your project requires ASTM A105N WN flange, special bore dimensions, SCH 160, NACE MR0175 or other project-specific requirements, send us your flange specification or drawing. Our engineering and production teams can review the requirements and provide a suitable quotation.