ASTM A335 P91 Large Diameter Boiler Pipe from Mexico
Seamless Grade P91 chrome-moly alloy steel pipe for elevated-temperature service in refining furnaces and supercritical boilers, with 508 mm OD. It provides excellent creep resistance for high-pressure feedwater heaters. Falls under 7304.59.20.80 as other alloy steel seamless tubes over 406.4 mm OD suitable for boilers and refining furnaces.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Import Tips
• Provide hydrotest and nondestructive electric test (NDT) certificates as required for P91 grade to prove pressure integrity
• Declare exact alloy elements (9% Cr, 1% Mo) in entry docs; mismatches lead to duty reassessment or penalties
• Avoid bundling with fittings; ship as individual lengths to prevent set classification under 7307 or 7308