Iron ore and scrap metal (60-70% of production costs) drive price volatility. A 10% iron ore rise (e.g., from 100 to 110/ton) increases flat steel prices by $30-50/ton. Energy costs (natural gas for steelmaking) add pressure-European prices spiked 200% in 2022, raising local flat steel by 30%. Carbon pricing (EU ETS) adds €30-50/ton for high-emission producers. Regional premiums exist: U.S. prices are 10-15% higher than China's due to tariffs and transportation. Stainless grades (304) cost 3-4x carbon steel, driven by nickel prices (25-30% of 304's cost). These factors create a global market where Chinese exports (20% of output) compete with regional producers like ArcelorMittal.