Stainless steel screwed (threaded) fittings follow strict material, dimension, and pressure standards. Sizes normally range from 1/8' to 4' NB. Common grades are SS 304/304L and SS 316/316L, built to standards like ASME B16.11 and ASTM A182, utilizing NPT or BSP thread types. Key Specifications & Standards • Material Grades: ASTM A182 / ASME SA182 (Forged), ASTM A351 / A276 (Cast) — Grades 304, 304L, 316, 316L. • Dimensions & Design: ASME B16.11 (Forged Threaded Fittings), MSS SP-79, MSS SP-83, MSS SP-95, and BS 3799. Class 150 cast fittings follow ISO 4144 or MSS SP-114. • Size Range: 1/8 inch to 4 inch NB (nominal bore) for standard fittings; nipples can extend up to 6 inches. • Pressure Ratings / Classes: • Class 150 (Low pressure, threaded cast) • Class 2000 (Equivalent to Schedule 80 / XS) • Class 3000 (Equivalent to Schedule 160) • Class 6000 (Equivalent to Schedule XXS) Thread Types • NPT (National Pipe Thread): 60° thread angle, tapered threads common in North America. • BSP / BSPT / BSPP (British Standard Pipe): 55° thread angle, available in tapered (BSPT) or parallel (BSPP) forms common globally. Common Fitting Types • 90° & 45° Elbows • Equal & Reducing Tees • Full & Half Couplings • Hex Bushings & Plugs • Pipe Nipples & Unions • Caps & Crosses If you're working on a specific project, please let me know:The pressure class or application (e.g., steam, water, oil/gas)The required thread type (NPT or BSP)The specific fitting type and size you needI can help you narrow down the exact configuration or material grade required. AI responses may include mistakes.