1. Mechanical Properties per JIS G3114
| Property | Requirement for SMA400AW | Test Standard |
|---|---|---|
| Yield Strength (Re) | ≥ 245 MPa (min) | JIS Z 2241 (ISO 6892-1) |
| Tensile Strength (Rm) | 400–510 MPa | JIS Z 2241 |
| Elongation (A) | ≥ 17% (for thickness ≤16mm) | JIS Z 2241 |
| Charpy Impact | ≥ 27 J at 0°C (min) | JIS Z 2242 (ISO 148-1) |
| Bend Test | No cracks at 180° bending (t=plate thickness) | JIS Z 2248 |
2. Chemical Composition Limits (JIS G3114)
The corrosion resistance of SMA400AW is achieved through alloying elements:
C (Carbon): ≤0.20%
Si (Silicon): 0.10–0.50%
Mn (Manganese): 0.50–1.50%
P (Phosphorus): ≤0.035%
S (Sulfur): ≤0.035%
Cu (Copper): 0.25–0.55% (critical for patina formation)
Cr (Chromium): 0.30–1.25%
3. Equivalent International Standards
SMA400AW is comparable to other weathering steel grades globally:
ASTM A588/A242 (USA) – Similar corrosion resistance but slightly different mechanical ranges.
EN 10025-5:2019 (Europe) – Grades like S355J0WP or S355J2W+N.
GB/T 4171 (China) – Q355NH or Q355GNH.
4. Key Testing & Certification Standards
Tensile/Impact Tests: Conducted per JIS Z 2241/2242 (aligned with ISO 6892-1 and ISO 148-1).
Corrosion Testing: Evaluated via cyclic corrosion tests (e.g., ISO 9223/9227 for atmospheric exposure).
Certification: Mill test certificates (MTC) must comply with JIS G0415 (steel product inspection standards).
5. Design & Application Standards
Structural Use: JIS G3106 (general structural steel standards).
Welding: Follow JIS Z 3312 for welding materials compatible with weathering steel.
Corrosion Allowance: Design per JIS G3192 (thickness tolerances for corrosion-prone environments).
6. Comparison with Other SMA Grades
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Key Difference |
|---|---|---|---|
| SMA400AW | ≥245 | 400–510 | Standard weathering grade |
| SMA490AW | ≥325 | 490–610 | Higher strength, better corrosion resistance |
| SMA570W | ≥450 | 570–720 | For heavy-load structures |
Recommendations for Engineers
Specify JIS G3114 in procurement documents to ensure compliance.
Verify MTCs for actual test values (especially impact toughness in cold climates).
For non-Japanese projects, confirm equivalence with local standards (e.g., ASTM A588 for US projects).
