Carbon Steel Flange 18-Inch ID
A large carbon steel flange with an inside diameter of 450 mm, designed for connecting pipes in industrial water supply systems. It falls under HTS 7307.91.5050 as a flange of iron or nonalloy steel with an inside diameter exceeding 360 mm. These are typically used in heavy-duty piping for their durability and weldability.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If made of alloy steel
Alloy steel flanges (with elements like chromium >0.5%) shift to the 'other steel' flange category under the same size criteria.
If with inside diameter under 360 mm
Flanges smaller than 360 mm ID are classified in the preceding subheading regardless of material.
If sold as a pipe flange weldment set
If imported as a complete welded pipe assembly rather than standalone flange, it may classify under stainless/nonalloy tube/pipe headings.
Not sure which classification is right?
Our AI classifier can analyze your specific product and recommend the correct HTS code with confidence.
Import Tips & Compliance
• Verify inside diameter measurement exceeds 360 mm with precise caliper documentation to avoid misclassification to smaller flange subheadings
• Provide mill test certificates confirming nonalloy steel composition (max 0.25% carbon) for customs valuation and anti-dumping checks
• Ensure markings for pressure rating (e.g
• ANSI 150#) to demonstrate compliance with ASME B16.5 standards
Related Products under HTS 7307.91.50.50
Nonalloy Steel Weld Neck Flange 400 mm ID
Weld neck flange of nonalloy steel with 400 mm inside diameter, featuring a long tapered hub for high-pressure pipeline connections in oil refineries. Classified under HTS 7307.91.5050 due to its iron/nonalloy steel construction and large bore size. Provides superior strength for butt-weld attachment.
Heavy Duty Iron Flange 14-Inch Schedule 40
Cast iron flange equivalent in nonalloy steel with 355 mm ID for schedule 40 pipes, used in municipal water treatment plants. Meets HTS 7307.91.5050 as iron/nonalloy steel flange over 360 mm ID threshold. Offers corrosion resistance for wastewater systems.
ASTM A105 Large Bore Flange 500 mm ID
Forged ASTM A105 carbon steel flange with 500 mm inside diameter for high-temperature steam lines in power plants. HTS 7307.91.5050 applies to this nonalloy steel fitting due to size and material specs. Rated for 300 psi at 400°F service.
Nonalloy Steel Blind Flange 16-Inch ID
Blind flange of nonalloy steel with 406 mm ID, used to seal pipe ends in chemical processing plants. Classifies under HTS 7307.91.5050 for large iron/nonalloy steel flanges. Full face gasket design for bolt-down pressure containment.
Carbon Steel Slip-On Flange 450 mm ID
Slip-on carbon steel flange with 450 mm bore for low-pressure process piping in food processing. HTS 7307.91.5050 covers this nonalloy steel large-diameter fitting. Fillet weld both sides for easy field installation.
Large Nonalloy Steel Plate Flange 600 mm ID
Plate flange cut from nonalloy steel plate stock, 600 mm inside diameter for ventilation ducting. Falls under HTS 7307.91.5050 as oversized iron/nonalloy flange. Economical choice for low-pressure HVAC systems.