ASTM A350 LF3 ANSI B16.5/B16.47 Alloy Steel Slip-On Flanges

Product Information

Standards & Materials: ASTM A1350 Grade LF3

Pipe flanges made from ASTM A350 Grade LF3 are generally used in low temperature services with notch toughness testing requirements. The ASTM A350 Grade LF3 refers to a low-alloy steel designated as “3.5% nickel steel” or “3.5-Ni steel”. The deliberately controlled addition of nickel content can reduce the brittle-ductile transition temperature, whereupon improve its low temperature notch toughness significantly. The flanges may be manufactured in accordance with ASME B16.5 or ASME B16.47, or custom-designed.

Chemical Composition of ASTM A182 F11 Alloy Flanges

Mechanical Properties of ASTM A182 F11 Alloy Flanges

Charpy V-Notch Impact Test

Flanges made from ASTM A350 LF3 Class 1 or Class 2 shall take the Charpy V-notch impact test at a standard testing temperature of -150°F [-101°C]. The specimens shall be prepared in three pieces in size of 10 by 10 mm with the same heat number of the flange. The minimum impact energy required for average of each set of three specimens shall be 15 ft*lbf [20 J] for Class 1 and 20 ft*lbf [27 J] for Class 2; The minimum impact energy required for each one specimen only is 12 ft*lbf [16J] for Class 1 and 15 ft*lbf [20 J] for Class 2.

Flange Type: Slip On (SO)

Slip on flange also simplified as SO flange. SO flanges slip over pipes and are designed to bit slightly bigger on the inside than the pipe. They connect to the pipe through a fillet weld at the flange top and bottom. It is used to insert the pipe into the inner hole of flange, as the flange inner diameter is little bigger than the pipe’s outer diameter, pipe and flange could be connected by lap welding at the top and bottom of the flange.

The slip on flange is shorter in length than a weld neck flange, and is used in areas where short tie-ins are necessary or space limitations necessitate its use. Generally, the life span of a slip-on flange connection is about one-third that of the weld neck flange. Despite of additional welding involved during installation, its lower initial cost makes the SO flange preferred over WN flanges by many users. It is generally used in non-corrosive, non-critical, moderate pressure services. Slip on flanges of Class 150 and Class 300 are most commonly seen in utility engineering

Manufacturing Process

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