The inventory turnover rate (annual sales/average inventory) for round steel ranges from 4 to 7 times/year, varying by grade and diameter:
1) High-turnover items: Common grades/diameters like Q235B Φ16, Φ20, and 45# Φ25 have a turnover rate of 6-7 times/year, as they are used in mass-produced parts (bolts, small shafts);
2) Medium-turnover items: Q355B Φ30-Φ50 and 304 Φ10-Φ15 have a turnover rate of 4-5 times/year, for medium-load components (mechanical supports, food machinery parts);
3) Low-turnover items: Large diameters (Φ100+) and special grades (40Cr Φ80) have a turnover rate of 2-3 times/year, used in heavy machinery (large shafts).
Seasonality affects turnover-peaks in Q2/Q3 (manufacturing 旺季) at 0.7-0.8 times/quarter, drops to 0.4-0.5 times/quarter in Q4 (winter slowdown).