Find HS Code and trade information for flange

Flange

A flange is a projecting rim, edge, hub or collar used to connect pipes, tubes, fittings, valves, pumps or other equipment. They are typically, but not exclusively, welded or screwed onto the end of a pipe and then bolted together to form a connection. Flanges are critical components in piping systems, enabling easy disassembly for maintenance, inspection, or repair, and providing a strong, reliable seal.

Materials

Flanges are manufactured from a wide variety of materials, selected based on the application's pressure, temperature, and the fluid being conveyed. Common materials include:

• Carbon Steel: Most common for general-purpose applications, offering strength and affordability. Various grades exist, such as A105, each with specific properties.
• Stainless Steel: Used in corrosive environments or applications requiring high hygiene, such as food processing and pharmaceuticals. Common grades include 304/304L and 316/316L.
• Alloy Steel: Employed in high-temperature, high-pressure, or specialized applications.
• Cast Iron: Used for low-pressure, non-corrosive applications.
• Ductile Iron: Offers higher strength and ductility than cast iron.
• Aluminum: Used in applications where weight is a concern.
• Titanium: Used in highly corrosive environments and applications requiring extreme strength-to-weight ratios.
• Polymers (PVC, CPVC, PTFE): Used for low-pressure, corrosive applications.

Purpose & Function

The primary purpose of a flange is to provide a secure, leak-proof connection between piping components. Key functions include:

• Joining Pipes: Connecting sections of pipe together.
• Connecting Valves, Pumps, and Equipment: Attaching components to the piping system.
• Facilitating Disassembly: Allowing for easy removal for maintenance, inspection, or replacement of components.
• Providing a Sealing Surface: Creating a tight seal between two mating surfaces using gaskets.
• Distributing Load: Spreading the force of the connection evenly around the pipe or component.

Usage Scenarios

Flanges are used across a broad range of industries and applications, including:

• Oil & Gas: Pipelines, refineries, offshore platforms.
• Chemical Processing: Handling corrosive chemicals.
• Water & Wastewater Treatment: Pumping stations, treatment plants.
• Power Generation: Steam lines, cooling systems.
• HVAC: Heating and cooling systems.
• Pharmaceuticals: Hygiene-critical processes.
• Food & Beverage: Sanitary piping systems.
• Construction: Plumbing and drainage systems.

Common Types

Flanges are classified based on several factors, including connection type, shape, and pressure rating. Some common types include:

• Weld Neck Flange: Welded to the pipe, providing a strong, high-pressure connection. Commonly used in high-pressure, high-temperature applications.
• Slip-On Flange: Slipped over the pipe and welded in place. Easier to install than weld neck flanges.
• Socket Weld Flange: Welded inside the flange socket. Used for smaller pipe sizes and lower pressure applications.
• Blind Flange: Used to seal the end of a pipe or close a connection.
• Threaded Flange: Screwed onto the pipe. Used for smaller pipe sizes and lower pressure applications.
• Lap Joint Flange: Used with a stub end, providing a lower-cost connection.
• Stub End: Used in conjunction with lap joint flanges.
• Reducing Flange: Used to connect pipes of different sizes.
• Spectacle Blind Flange: A combination of a full blind flange and a reducing flange, used for temporary isolation.

Standards

Flange dimensions and specifications are governed by several international standards, including:

• ANSI/ASME B16.5: Pipes, flanges, and fittings (most common in North America).
• EN 1092-1: Steel flanges and bolted connections (common in Europe).
• JIS B2220: Steel pipe flanges (common in Japan).
• DIN: German standards for various flange types.

Based on the provided information, flanges fall under various classifications depending on the material and specific application. Here's a breakdown of relevant HS codes:

• 7308903000: Structures (excluding prefabricated buildings of heading 9406) and parts of structures (for example, bridges and bridge sections, lock gates, towers, lattice masts, roofs, roofing frameworks, doors and windows and their frames and thresholds for doors, shutters, balustrades, pillars and columns) of iron or steel; plates, rods, angles, shapes, sections, tubes and the like, prepared for use in structures, of iron or steel: Other: Columns, pillars, posts, beams, girders and similar structural units: Not in part of alloy steel. This code covers iron or steel structural parts, and flanges used as part of a larger structure would fall under this classification.

  • Chapter 73: Iron or steel manufactures.
  • Heading 7308: Structures and parts of structures (excluding prefabricated buildings).
  • Subheading 730890: Other structures and parts.
  • Subheading 73089030: Specifically for columns, pillars, posts, beams, girders, and similar units not made of alloy steel.

• 7308906000: Structures (excluding prefabricated buildings of heading 9406) and parts of structures (for example, bridges and bridge sections, lock gates, towers, lattice masts, roofs, roofing frameworks, doors and windows and their frames and thresholds for doors, shutters, balustrades, pillars and columns) of iron or steel; plates, rods, angles, shapes, sections, tubes and the like, prepared for use in structures, of iron or steel: Other: Columns, pillars, posts, beams, girders and similar structural units: Other. This code also covers iron or steel structural parts, but for those not specifically categorized in 73089030.

  • Chapter 73: Iron or steel manufactures.
  • Heading 7308: Structures and parts of structures (excluding prefabricated buildings).
  • Subheading 730890: Other structures and parts.
  • Subheading 73089060: Specifically for columns, pillars, posts, beams, girders, and similar units, with no alloy steel specification.

• 8307103000: Flexible tubing of base metal, with or without fittings: Of iron or steel: With fittings. If the flange is part of a flexible tubing assembly made of iron or steel, this code applies.

  • Chapter 83: Miscellaneous manufactured articles of base metal.
  • Heading 8307: Tube or pipe fittings of base metal.
  • Subheading 830710: Of iron or steel.
  • Subheading 83071030: Specifically for fittings with fittings.

• 8307106000: Flexible tubing of base metal, with or without fittings: Of iron or steel: Other. If the flange is part of a flexible tubing assembly made of iron or steel, but is not specifically categorized in 83071030, this code applies.

  • Chapter 83: Miscellaneous manufactured articles of base metal.
  • Heading 8307: Tube or pipe fittings of base metal.
  • Subheading 830710: Of iron or steel.
  • Subheading 83071060: Specifically for fittings without fittings.

The applicable tariff for all of the above codes is 80.0% (0.0% basic tariff + 25.0% additional tariff + 25.0% steel/aluminum additional tariff). After April 2, 2025, the additional tariff will increase to 30.0%.

Please note that the specific HS code will depend on the material composition and the function of the flange. If the flange is part of a larger assembly, the entire assembly may have a different HS code.