75*75*6mm MID Steel Angle Iron Metal Angles From China Manufacturer Angle Steel ASTM A36 A53 Q235 Q345 Carbon Equal Angle Steel Galvanized Iron L Shapel Angle

What is the standard for Q235?
A: GB/T 700-2006 (Carbon Structural Steels).
 What are the equivalent grades of Q235?
A:
International: S235JR (EN 10025), A36 (ASTM), SS400 (JIS)
China: Q235A/B/C/D; old A3.
 What defects are common in Q235?
A: Surface: Rust, scratches, scale; Internal: Porosity, inclusions, segregation (due to low-grade steelmaking).
 How to inspect Q235 quality?
A:
Mechanical: Yield/tensile, elongation, impact, cold bend
Chemical: C, Mn, Si, S, P
Visual: Surface, dimension, marking.
 Can Q235 be used for pressure vessels?
A: Not for high-pressure vessels. Allowed for low-pressure, non-critical vessels (≤1.6MPa, mild temp) per GB 150.