Carbon steel (CS) butt weld fittings are piping components welded end-to-end to change flow direction, branch, or alter pipe sizes. They typically conform to ASTM A234 WPB for material properties and ASME B16.9 for factory-made dimensions, covering sizes from ½' to 48' NB across multiple wall thickness schedules. Core Material Specifications • Standard Specification: ASTM A234 / ASME SA234 (WPB is the most common grade for moderate and high-temperature service). • High-Yield/Low-Temp Grades: ASTM A420 (low temperature), ASTM A860 (high yield). • Tensile Strength: Minimum 415 MPa (60, 200 psi) for WPB. • Yield Strength: Minimum 240 MPa (34, 800 psi) for WPB. Dimensional & Design Standards • ASME B16.9: Factory-made wrought buttweld fittings (NPS ½' to 48'). • ASME B16.28: Short radius elbows and returns. • MSS SP-75: Specification for high-test wrought welding fittings. • ASME B16.25: Butt-welding end preparations (bevel angles, root faces). Size and Wall Thickness Schedules • Size Range: ½” NB to 48” NB (DN15 to DN1200). • Wall Thickness (Schedules): SCH 10, SCH 20, STD, SCH 40, XS, SCH 80, SCH 100, SCH 120, SCH 140, SCH 160, and XXS. [2] Common Fitting Types • Elbows: 45°, 90°, and 180° (available in both Long Radius [LR] and Short Radius [SR]). • Tees: Equal tees and reducing tees. • Reducers: Concentric and eccentric reducers. • Other Types: Pipe caps, lap joint stub ends, and lateral branch connections. AI responses may include mistakes.