What are the different types of weld pipe fittings?

Butt Welding (BW) and Socket Welding (SW)
Butt Weld Fittings: Manufactured according to standards such as ASME B16.9, the pipe ends are usually beveled, directly butt-welded into the pipe with full penetration. They have extremely high structural strength and are suitable for high-pressure, large-diameter, and harsh corrosive environments.
Socket Weld Fittings: Manufactured according to ASME B16.11, the pipe is directly inserted into the socket of the fitting for fillet welding. Primarily used for small-diameter (typically ≤2 inches) pipes and pipelines carrying toxic or flammable media with a high risk of leakage.

Core Fitting Types and Functions
Elbows: Used to change the direction of pipe flow. The most common types are 45° and 90° elbows. They are classified by radius of curvature as long radius (LR) and short radius (SR).
Tees & Crosses: Used for fluid convergence or divergence. Equal tees have the same branch pipe diameter as the main pipe; reducing tees are used to connect smaller diameter branch pipes in process lines.
Reducers: Enable smooth transitions between pipes of different diameters. Concentric reducers are commonly used for vertical pipes; eccentric reducers keep the bottom edge horizontal and are often used at pump inlets to prevent cavitation.

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