Weld Neck flanges are the highest-pressure rated flange type — a tapered hub provides smooth stress transition at the weld joint. Commonly referenced to ASME B16.5.
Weld Neck (WN) flanges are the highest-pressure rated flange type. A tapered hub provides smooth stress transition from the flange face to the pipe, making them the preferred choice for critical high-pressure and high-temperature piping systems. The butt-weld connection allows full penetration welds that maintain the same pressure-containing capacity as the pipe itself. WN flanges are forged as a single piece, providing the most structurally rigid flange joint among the six flange types.
Supply is reviewed per inquiry against standard, pressure class, NPS, grade and facing. Grade 2 CP titanium and Grade 5 (Ti-6Al-4V) are the most commonly requested grades for WN flanges. Grade 1, 7, 9, 12 and Grade 23 (Ti-6Al-4V ELI) can be evaluated per inquiry.
Reviewed against your required standard, pressure class and nominal pipe size.
ASME B16.5 is the primary standard for WN flange dimensions and pressure-temperature ratings. ASME B16.34 reviewed for valve flange ends. Regional standards such as EN 1092-1 and JIS B2220 coordinated per inquiry.
Class 150 through Class 2500 per ASME B16.5. Pressure class selection depends on operating temperature and pressure. Higher classes generally require thicker flanges and larger bolt diameters.
Industry Standard: NPS ½ through NPS 24 per ASME B16.5. Custom Manufacturing: larger and non-standard sizes evaluated per request. Actual Supply Availability confirmed per inquiry against grade, pressure class and quantity.
Critical high-pressure connections in acid, solvent and corrosive process lines.
Tube-side and shell-side flange connections for titanium heat exchangers.
High-integrity flange connections in marine and underwater titanium piping systems.
Most commonly ASME B16.5 for standard dimensions and pressure-temperature ratings. Alternative standards such as EN 1092-1 or JIS B2220 can be reviewed per inquiry.
RF (Raised Face) is the most common for process piping. RTJ (Ring Type Joint) is preferred for higher-pressure Class 900 and above applications. Facing must match the mating flange.
WN flanges have a tapered hub butt-welded directly to the pipe for full structural rigidity and highest pressure ratings. SO flanges slip over the pipe and are fillet-welded on both sides for lower cost but limited to moderate pressure classes (typically Class 150 and Class 300).
Please specify the standard (e.g., ASME B16.5), pressure class (e.g., Class 300), nominal pipe size (NPS), grade, facing (RF / RTJ / FF) and quantity. We will confirm availability and supply conditions. For drawing-based or custom requirements, you may share your drawings with our sales team by email or WhatsApp after initial contact. Include material grade, dimensions, tolerances, quantity and drawing reference.
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