Incoloy 825 flange is specifically engineered for applications requiring frequent assembly and disassembly or for systems using expensive piping where only the stub end needs to be of high-alloy material.
The Lap Joint Flange system consists of two separate pieces: a flat, circular flange and a stub end (or "lap"). The stub end is butt-welded to the pipe, while the backing flange rotates freely around it. This design eliminates issues with bolt hole alignment, simplifies installation, and is ideal for systems prone to corrosion or erosion, as only the stub end needs replacement.
All dimensions and manufacturing of these flanges adhere strictly to the ASTM B564/ASME SB564 standard, ensuring material integrity and performance under pressure, temperature, and corrosive conditions.
Incoloy 825 Lap Joint Flange Specifications and Standards
Incoloy 825 Lap Joint Flanges are produced under a global framework of standards to ensure interchangeability and safety.
Material & Manufacturing Standard: ASTM B564 / ASME SB564. This standard covers the requirements for nickel-alloy forgings, including the chemical composition, mechanical properties, heat treatment, and testing.
Dimensional Standards: The physical dimensions are governed by pipe flange standards such as ANSI/ASME B16.5 (for sizes up to 24") and ASME B16.47 Series A & B (for larger diameters). Other recognized standards include DIN, EN 1092-1, BS 4504, and MSS SP-44.
Pressure Class Ratings: These flanges are available in standard pressure classes to match system requirements. The common classes include:
ANSI Classes: 150, 300, 600, 900, 1500, 2500.
PN (Pressure Nominal) Ratings: PN6, PN10, PN16, PN25, PN40, PN64.
ASME B16.5 Lap Joint Flange Dimension
For Incoloy 825 lap joint flanges sized NPS ½" to 24", key dimension include:
|
Parameter |
Description |
|
Flange Outside Diameter (OD) |
Varies by NPS and pressure class (e.g., Class 150 2" flange: 6.00"; Class 600 2" flange: 7.50") |
|
Bore Diameter |
Sized to accept the stub end OD with rotational clearance (typically 1/16" to 1/8" larger than stub end OD) |
|
Flange Thickness |
Increases with pressure class (e.g., Class 150 4" flange: 0.62"; Class 900 4" flange: 1.38") |
|
Bolt Circle Diameter |
Determined by NPS and class (e.g., Class 150 4" flange: 9.00") |
|
Hub Dimensions |
Lap joint flanges feature a short, straight hub without taper |
Pressure Classes and Ratings
To suit varying operational pressures, these flanges are engineered across multiple rating systems:
|
Rating System |
Available Classes |
|
ANSI |
Class 150, 300, 600, 900, 1500, 2500 |
|
DIN |
6Bar, 10Bar, 16Bar, 25Bar, 40Bar, PN6, PN10, PN16, PN25, PN40, PN64 |
|
JIS |
5K, 10K, 16K, 20K, 30K, 40K, 63K |
|
UNI |
6Bar, 10Bar, 16Bar, 25Bar, 40Bar |
|
EN |
6Bar, 10Bar, 16Bar, 25Bar, 40Bar |
These pressure ratings, compliant with ASTM B564 and ANSI/ASME B16.5, enable safe operation under high-stress conditions while maintaining dimensional accuracy.
Lap Joint Flanges Dimension Information
When specifying an Incoloy 825 Lap Joint Flange, several dimensions are crucial for a leak-proof and safe assembly. It is imperative to consult the relevant dimensional standard (e.g., ASME B16.5) for the exact measurements based on the Nominal Pipe Size (NPS) and Pressure Class.
Key dimensions to specify include:
Outside Diameter (OD): The overall diameter of the flange.
Thickness (T): The thickness of the flange plate.
Bolt Circle Diameter (BC): The diameter of the circle connecting the centers of the bolt holes.
Number & Diameter of Bolt Holes: Determined by the size and class.
Bore Diameter: Must match the outer diameter of the accompanying stub end.
Note on Compatibility: The Lap Joint Flange itself does not come into contact with the process fluid. Therefore, the stub end, which is butt-welded to the pipe, must be of a matching material (Incoloy 825) and have identical dimensions (outside diameter, wall thickness) to ensure a proper weld and sealing surface.
ASTM B564 Incoloy 825 Lap Joint Flange Applications
Due to their outstanding resistance to both oxidizing and reducing media, ASTM B564 Incoloy 825 Lap Joint Flanges are the preferred choice in some of the most aggressive industrial environments:
Chemical & Petrochemical Processing: For handling sulfuric and phosphoric acids, acid chlorides, and solvents.
Oil & Gas Production: In components exposed to sour gas (H₂S), carbon dioxide, and saline downhole conditions.
Pollution Control & Marine Engineering: In scrubber systems, seawater handling, and offshore platforms.
Pharmaceutical and Acid Production: Where ultra-pure and corrosion-resistant alloy systems are mandatory.
In summary, specifying the correct size for an ASTM B564 Incoloy 825 Lap Joint Flange requires a clear understanding of three interdependent factors: the system's pressure class, the nominal pipe size, and the governing dimensional standard.
When these are aligned with the superior corrosion resistance of Incoloy 825, the result is a durable, maintainable, and cost-effective solution for critical piping connections. For precise dimensional charts for a specific size and class, engineers should refer directly to the tables within the ASME B16.5 or other applicable standards.
