Socket Raised Face Weld Neck Flange , Class 300 Carbon Steel SW RF Flange

ASTM A105N ANSI B16.5 SW RF Class 300 Carbon Steel Socket Weld Raised Face Flange

Product Information

ASTM A105/A105N

ASTM A105 flanges are forged carbon steel flanges for ambient- and higher-temperature service in pressure systems. These flanges may be manufactured in accordance with a variety of standard specifications covering ASME B16.5, ASME B16.47, ASME B16.48, ASME B16.36, MSS SP 44, API 605, and API 6A, etc. Flanges made to ASTM A105 material are limited a maximum weight of 4540 kg.

ASTM A105 and A105N steel flanges are not same, they have same raw materials, same steel grades, but different heat treatment requirement. N means Normalization heat treatment, and A105 flange haves no heat treatment requirement. In summary, the ASTM A105 flange and ASTM A105N flange have a same chemical composition, but the A105N have a better mechanical property and usually used in critical situation.

ASTM A105 Chemical Composition (%)

ASTM A105 Mechanical Properties

Flange Type:Weld Neck Flange (WN)

Socket Weld flanges were initially developed for use on small-size high pressure piping. Their static strength is equal to Slip On flanges, but their fatigue strength 50% greater than double-welded Slip On flanges.

The connection with the pipe is done with 1 fillet weld, at the outside of the flange. But before welding, a space must be created between flange or fitting and pipe.

ASME B31.1 1998 127.3 Preparation for Welding (E) Socket Weld Assembly says..
In assembly of the joint before welding, the pipe or tube shall be inserted into the socket to the maximum depth and then withdrawn approximately 1/16" (1.6 mm) away from contact between the end of the pipe and the shoulder of the socket.

The purpose for the bottoming clearance in a Socket Weld is usually to reduce the residual stress at the root of the weld that could occur during solidification of the weld metal. The image shows you the X measure for the expansion gap.

1. Socket Wedl Flange 2. Filled Weld 3. Pipe X=Expansion gap

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)