Our black steel couplings are manufactured in strict compliance with ASTM A865, with sizes available from 1/8 inch to 6 inches. The threads are produced in accordance with ASME B1.20.1 standards. We provide flexible packaging options, fast delivery, and lower pricing, making us a trusted supplier for global distributors, wholesalers, and contractors.
Black steel couplings are manufactured in accordance with ASTM A865, with available sizes ranging from 1/8 inch to 6 inches.
The threads comply with ASME B1.20.1 standards:
1/8" to 2" couplings are produced with straight (NPS) threads.
2 1/2" to 6" couplings are produced with tapered (NPT) threads.
The processing of NPS (National Pipe Straight) thread fittings is simpler than that of NPT (National Pipe Taper) thread fittings. NPS couplings are commonly used in low-pressure and non-sealed applications, where sealing performance is not critical.
In contrast, NPT couplings are designed for sealed connections, making them suitable for transporting gases and liquids, which require higher precision and tighter sealing.
In the U.S. market, NPT threads are the more widely adopted standard, while NPS couplings are generally more cost-effective due to lower processing and sealing requirements.
