Large Diameter Weld Neck Flange

Large Diameter Weld Neck Flange(also known as large-bore WN flange)is a high-strength piping connection component engineered for NPS 26–60(DN650–DN1500)large-diameter pipeline systems.It features a one-piece forged structure with a long tapered hub,designed to butt-weld directly to pipes,ensuring exceptional structural integrity,stress distribution,and leak-tight performance under extreme service conditions.

Core Design&Structure

Tapered Hub:A long,gradually tapering neck transitions smoothly from the flange rim to the pipe’s inner diameter(ID).This design minimizes stress concentration at the weld joint,distributes mechanical loads evenly,and reduces turbulence for efficient fluid flow.

Butt-Welded Connection:The beveled end of the hub is welded to the pipe via a full penetration butt weld,forming a continuous,integral joint that eliminates weak points and withstands high pressure/temperature cycles.

Flange Rim:A circular plate with precisely drilled bolt holes(20–48 holes,depending on size/pressure rating)for bolted assembly.Common face types include Raised Face(RF,0.06”standard)and Ring-Type Joint(RTJ)for high-pressure sealing.

Forged Construction:Manufactured from solid steel forgings(not cast)to ensure uniform grain structure,superior mechanical properties,and resistance to cracking under heavy loads.

Critical Advantages

Superior Strength&Reliability:The tapered hub and forged design handle high internal pressure,thermal expansion,and external bending loads,making it the preferred choice for critical large-diameter pipelines.

Leak-Tight Performance:Butt-welding eliminates gaps,while RF/RTJ faces ensure tight gasket seals,reducing leak risks in hazardous fluid(oil,gas,chemicals)applications.

Flow Efficiency:Smooth bore matching the pipe ID minimizes flow resistance,erosion,and pressure drop—ideal for high-capacity transmission lines.

Long-Term Durability:Resists fatigue,corrosion,and deformation under cyclic loading,lowering maintenance costs and extending service life.

Primary Applications

Oil&gas transmission pipelines(crude oil,natural gas)

Refineries and petrochemical plants(high-temperature/high-pressure process lines)

Water treatment and desalination facilities(large-volume water pipelines)

Power generation(thermal/hydroelectric power plant piping systems)

Heavy industrial projects(mining,steel mills,large-scale infrastructure)