EN 10025-4 (EU) and GB/T 1591 Q420 (China) cover high-strength thermomechanically rolled round bars, with key similarities and differences:
Strength levels: EN 10025-4 S420MC has a 420 MPa minimum yield strength, matching Q420's 420 MPa, making them suitable for weight-sensitive structures.
Chemistry: Both use microalloys (Nb, V, Ti) to achieve strength without excessive carbon, but S420MC allows higher manganese (1.60% max vs. 1.70% max for Q420).
Toughness: EN 10025-4 mandates -40°C impact toughness (≥27 J) for S420MC, while Q420D requires -20°C toughness (≥34 J)-reflecting regional climate needs.
Applications: S420MC is used in EU automotive frames (to reduce weight), while Q420 dominates Chinese bridge construction, with cross-compatibility in global projects.