ASME B16.9 Stub End Fittings Stainless Steel Lap Joint Stub End SCH40 SCH80 attach the Lap Joint Flange to Pipe Systems

Description of ASME B16.9 Stainless Steel Lap Joint Stub Ends:

The ASME B16.9 Lap Joint Stub is a type of pipe fitting used to connect pipes with lap joint flanges in industrial piping systems. It consists of a short piece of pipe with one end that has a standard wall thickness and the other end that is thinner to accommodate the flange. The thinner end of the stub end slides into the flange, while the other end is butt-welded to the pipe.

ASME B16.9 Lap Joint Stubs are commonly used in applications where frequent dismantling or maintenance is required, as they allow for easy disassembly without disturbing the alignment of the flange and piping system. They provide flexibility and convenience in piping systems that need to be adjusted or inspected regularly.

These fittings come in two main types: long pattern and short pattern, each designed to meet specific requirements based on the piping system's configuration and operating conditions. ASME B16.9 sets the standards for the dimensions, materials, and tolerances of lap joint stub ends to ensure compatibility and reliability in various industrial applications.

ASME B16.9 Lap Joint Stub Ends Dimensions:

Notes:

• 1. Gasket Face Finish: The gasket face finish for raised face flanges should adhere to the standards outlined in ASME B16.5. This ensures compatibility and proper sealing between mating flange surfaces.

• 2. Lap Thickness: The lap thickness, denoted as "T," must not be less than the nominal pipe wall thickness. This ensures adequate material overlap for secure welding and joint integrity.

• 3. Stub End Length: Depending on the flange class and size, adjustments to the length of short or long pattern stub ends may be necessary to prevent the weld from being covered by the flange. This ensures proper alignment and welding accessibility.

• 4. Special Facings: When employing special facings such as tongue and groove, male and female, etc., additional lap thickness should be provided, beyond the basic length "F," to accommodate these special facing requirements.

• 5. Fillet Radius and Lap Diameter: The dimensions of the "Radius of Fillet, R" and "Diameter of Lap, G" should conform to the standard dimensions established for lap joint flanges in ASME B16.5. This ensures consistency and compatibility with industry standards for lap joint connections.

Common Materials and Grades of ASME B16.9 Butt Weld Lap Joint Stub End:

1. Stainless Steel:

   • Grades: 304/304L, 316/316L, 317/317L, 321/321H, 347/347H
   • Stainless steel lap joint stub ends are widely used in applications requiring corrosion resistance, high-temperature strength, and durability. They are commonly used in industries such as chemical processing, food and beverage, pharmaceuticals, and oil and gas.

2. Carbon Steel:

   • Grades: ASTM A234 WPB, ASTM A860 WPHY42, WPHY46, WPHY52, WPHY60, WPHY65, WPHY70
   • Carbon steel lap joint stub ends are suitable for applications where high strength and resistance to mechanical stress are required. They are commonly used in industrial piping systems, power generation, and petrochemical plants.

3. Alloy Steel:

   • Grades: ASTM A234 WP1, WP5, WP9, WP11, WP22, WP91
   • Alloy steel lap joint stub ends are utilized in applications where enhanced mechanical properties, such as high-temperature strength and corrosion resistance, are necessary. They are commonly found in industries such as oil and gas, power generation, and chemical processing.

4. Duplex Stainless Steel:

   • Grades: S31803 (2205), S32205
   • Duplex stainless steel lap joint stub ends offer excellent corrosion resistance and high strength, making them suitable for demanding applications in chemical processing, offshore and marine environments, and desalination plants.

5. Nickel Alloys:

   • Grades: Alloy 200, 201, 400, 600, 625, 800, 825, C276
   • Nickel alloy lap joint stub ends are used in applications requiring exceptional resistance to corrosion, high temperatures, and aggressive chemical environments. They are commonly employed in chemical processing, aerospace, and marine industries.

Types of Lap Joint Stub Ends:

1. Type A Stub End:

   • Used for standard lap joint flanges
   • Lap thickness equal to or greater than the nominal wall thickness of the pipe
   • Outer corner radius suitable for lap joint flange
   • Inner corner is square with a machined serrated face

2. Type B Stub End:

   • Used for standard slip-on flanges as lap flanges
   • Lap thickness equal to or greater than the nominal wall thickness of the pipe
   • Outer corner radius suitable for slip-on flange as a backup flange
   • Inner corner is square with a machined serrated face

3. Type C Stub End:

   • Can be used for both lap joint and slip-on flanges
   • Flared design with a rounded edge at the inside diameter of the lap
   • Lap thickness is 75% of the pipe wall thickness
   • Lap joint is smooth and not machined

Common Types and Lengths:

• Stub ends are typically manufactured in Type A and Type B styles.
• Available in two standard lengths: long (ANSI) or short pattern (MSS).
• Schedule 5s and 10s stub ends usually come in short lengths, while schedule 40s stub ends can be supplied in short or long lengths.

Usages of ASME B16.9 Lap Joint Stub Ends:

Facilitating Flange Connections: Lap Joint Stub Ends are often used to facilitate flange connections in piping systems. They allow for easy alignment and assembly of flanges, especially in systems where frequent dismantling or maintenance is required.

Adjusting Pipe Length: Lap Joint Stub Ends are used to adjust the overall pipe length in a system without necessarily altering the pipeline itself. They help in making connections to various components such as valves, pumps, and other equipment.

Avoiding Welding Directly to Flanges: By using lap joint stub ends, welding is done between the stub end and the pipe, rather than directly to the flange. This can simplify installation, maintenance, and repairs by allowing for easy disassembly of the flange joint without cutting or re-welding.

Creating Non-Permanent Joints: In situations where temporary or non-permanent joints are needed, lap joint stub ends offer a convenient solution. They provide a way to connect pipes without the need for fully welded joints, allowing for easier disassembly when required.

Allowing Rotation in Flanged Connections: The use of lap joint stub ends permits rotation of the lap joint flange on the stub end, which can be beneficial for alignment purposes or when adjustments in orientation are needed.

Compatibility with Different Flange Types: Lap Joint Stub Ends are designed to work with lap joint flanges, as well as slip-on, socket weld, and threaded flanges, providing versatility in piping system configurations.

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