12-1/4 inch 75# C-110 Sour Service Casing from Canada
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 — Canada → United States
50%
Rate breakdown
9903.82.0250%Except as provided for in headings 9903.82.14, 9903.85.67 and 9903.85.68, articles of aluminum, of steel or of copper and derivative aluminum or steel articles, as provided for in subdivisions (c)(i)–(v) of U.S. note 16 to this subchapter
9903.05.900%Articles already subject to Section 232 (steel/aluminum/copper + derivatives, autos + parts, wood, medium/heavy vehicles + parts, semiconductors, patented pharma) — U.S. note 52(f)
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)