ASTM A182 F316/L ANSI B16.5 WN RF Class 300 Stainless Steel Weld Neck Raised Face Flange

ASTM A182 F316/L ANSI B16.5 WN RF Class 300 Stainless Steel Weld Neck Raised Face Flange

Stainless Steel Pipe Flanges Information

A stainless steel weld neck raised face  flange is a type of flange commonly used in high-pressure piping systems.

The weld neck raised face flange has a circular shape with a long tapered hub and a neck that extends from the flange body. The neck is designed to match the pipe's inside diameter and provides reinforcement to the connection. The raised face surface provides a sealing area for the gasket.

The weld neck flange is welded to the pipe by fillet welding both on the inside and outside of the flange. The butt weld joint between the neck and the pipe provides a strong and leak-resistant connection.

Stainless Steel Pipe Flanges Materials: ASTM A182 F316/F316L

Stainless steel weld neck raised face flanges are commonly made from austenitic stainless steel grades such as 304 (UNS S30400) and 316 (UNS S31600). These grades offer excellent corrosion resistance and mechanical properties suitable for various applications.

Stainless steel 316/ 316L flanges have enhanced resistance to pitting corrosion in chloride environments due to the addition of molybdenum. The letter “L” denotes low carbon content. According to ASME B16.5 and ASME B16.47, SS 316/ 316L flanges may be made from forgings of ASTM A182 Grade F316 or F316L, castings of ASTM A351 Grades CF8M or CF3M, and plates of ASTM A240 Grades 316 or 316L.

ASTM A182 F316/F316L Chemical Composition (%)

ASTM A182 F316/F316L Mechanical Properties

Flange Type:Weld Neck Flange (WN)

A weld neck flange, also called a tapered hub flange or high-hub flange, is a kind of flange that can relocate stress to the pipes, ensuring a decrease in high-stress concentration at the bottom of the flange. There are two welding neck flanges designs – the first type is used with pipes while the second, longer type cannot be used with pipes but with a process plant. The weld neck flange comprises of a round fitting that extends beyond the rim of the circumference. These flanges, typically manufactured from forging, are actually welded to pipes.

Face Type: Raised Face (RF)

The Raised Face flange is the most common type used in process plant applications, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face. This face type allows the use of a wide combination of gasket designs, including flat ring sheet types and metallic composites such as spiral wound and double jacketed types.

The purpose of a RF flange is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint. Diameter and height are in ASME B16.5 defined, by pressure class and diameter. Pressure rating of the flange determines the height of the raised face.

ANSI B16.5 Flange Dimensions – Class 300 (mm)