Socket Weld Fittings insert the pipe diagonally into the groove of the fitting and seal the connection using an angle weld, is a key component in piping systems for small-diameter pipe connections. How are socket weld fittings properly sized? Which of the different materials of socket weld fittings is better? Keep reading to help you learn more about this information and knowledge. Socket Weld Fittings Basic Performance and Size Chart Scope of application: Piping systems with nominal diameters ≤ NPS 2 Application scope: chemical industry, energy, ships and other fields.