Standard International Trade Classification
High-phosphorus nonalloyed pig iron, defined by a phosphorus content exceeding 0.50% by weight, serves a narrower set of foundry applications than its low-phosphorus counterpart — notably certain gray iron castings where phosphorus improves fluidity and machinability rather than causing harm. Like all pig iron, it is subject to Section 232 tariffs, and the phosphorus threshold is the sole specification boundary separating it from the lower-phosphorus grade in the same product family. Foundry buyers must specify phosphorus ranges precisely on purchase orders and import documentation to ensure correct classification and to meet metallurgical specifications for end-use castings. Chemical mill certificates remain the primary instrument for verifying compliance with the over-0.50% threshold.
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High-phosphorus pig iron is used in certain gray iron casting applications where phosphorus acts as a fluidizer, improving mold-filling in thin-section castings and enhancing machinability in the finished part. It is generally avoided in ductile iron and steel production where phosphorus above trace levels causes embrittlement. Foundries producing decorative castings, some automotive components, and machine tool parts have historically used this grade.
The threshold is 'not over 0.50%' for the lower heading versus 'over 0.50%' for this one, so a result of exactly 0.50% falls in the lower category. Because analytical methods carry measurement uncertainty, importers with borderline results should obtain multiple certified analyses and consider requesting a CBP binding ruling to lock in the classification before the shipment arrives.
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Imports · December 2025
origin
customs district
Census does not publish district detail for this classification system.
destination
Census does not publish state detail for this classification system.
entry
Census does not publish port detail for this classification system.
ImportsExports
Imports
—YoY · free account
Exports
—YoY · free account
Low of 1 reported month · imports
Low · free accountFewer than 6 of the last 12 months reported trade, or the latest month was under $500K; the trend chart is not shown for thin series.
Through December 2025 · imports 1 of 12 months reported, exports 1 of 12 months reported. Source: U.S. Census Bureau.