12-1/4 inch 75# C-110 Sour Service Casing from China
C-110 grade seamless alloy casing optimized for H2S sour service, 12-1/4 inch OD (311.2 mm within hierarchy), 75 lb/ft weight with thick walls ≥12.7 mm, full API STC couplings. Used to case wells with corrosive hydrogen sulfide content. Classified in 7304.29.31.40 for threaded, coupled, heavy-wall alloy steel oilfield casing.
Duty Rate — China → United States
35%
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
9903.91.0125%Effective with respect to entries on or after September 27, 2024, articles the product of China, as provided for in subdivision (b) of U.S. note 31 to this subchapter
Import Tips
• Certify NACE MR0175/ISO 15156 compliance for sour service; declare sulfide stress cracking test data
• Common issue: incorrect alloy content declaration affecting duty rates
• Bundle lengths must be specified (typically 40 ft)