A350 Gr. LF3 Class 150 RF Socket Welding Flange

This is a forged socket welding flange made from ASTM A350 Grade LF3 low-temperature carbon steel, manufactured in accordance with ASME B16.5, pressure rating Class 150 (150LB), with Raised Face (RF) sealing surface. The material contains 3.3%–3.7% nickel, with tensile strength of 485–655MPa and yield strength ≥260MPa. It is capable of service at ultra-low temperature down to -101℃, featuring stable Charpy impact energy, excellent resistance to brittle fracture and outstanding toughness under cryogenic conditions.

It adopts a socket-type design: pipes are inserted and welded internally and externally, ensuring strong connection and high sealing performance, suitable for 1/2"–4" pipe sizes. The RF face enables easy installation and compatibility with standard gaskets. It is widely used in harsh low-temperature applications including LNG, liquid nitrogen, low-temperature chemical engineering, oil and gas and other critical services.

Produced with full forging, heat treatment and complete inspection, the flange features precise dimensions and stable mechanical properties, fully meeting the safety and durability requirements of ASME-standard low-temperature pressure pipelines.