Slip on flange vs weld neck flange difference?

Slip On Flange vs Weld Neck Flange–Key Differences

1.Structural Design

Slip On Flange(SO Flange)

Short hub,smooth inner hole.The pipe slips through the flange bore,then welded on both inside and outside.Light weight,simple structure.

Weld Neck Flange(WN Flange)

Long tapered neck with gradual thickness transition.Integral forging structure,one-piece connected with pipe by full penetration butt weld.

2.Welding&Installation

Slip On Flange

Easy and fast installation,low welding skill requirement,short construction time,low labor cost.

Weld Neck Flange

Complex butt welding process,strict welding quality inspection needed,longer installation cycle and higher cost.

3.Pressure&Temperature Resistance

Slip On Flange

Suitable for low pressure,low temperature and general non-critical pipelines.Weak in stress resistance.

Weld Neck Flange

Excellent for high pressure,high temperature,vacuum and cyclic load working conditions.The tapered neck reduces stress concentration for stable performance.

4.Sealing&Safety

Slip On Flange

Weaker connection strength,easy to leak under shock or vibration.Not for hazardous medium.

Weld Neck Flange

High structural integrity,tight sealing,anti-vibration and anti-fatigue,ideal for oil,gas,chemical and pressure vessel systems.

5.Cost&Application

Slip On Flange

Cost-effective,widely used in water supply,drainage,ventilation and general industrial piping.

Weld Neck Flange

Higher price,applied in heavy industry,petrochemical,power and high-risk engineering projects.