Key Takeaways
- A633 GrA is an American-standard low-alloy high-strength structural steel plate, supplied in the normalised condition.
- "633" is the standard number, not a yield value: Gr.A yield strength is ≥290 MPa (42 ksi), tensile 430-570 MPa.
- It is a killed, fine-grain steel refined by oxygen converter or electric furnace, with high strength, toughness and weldability.
- Typical uses: hydraulic machinery, construction machinery, mining machinery and welded structural parts.
1. Grade Identification
A633A steel plate, also known as A633GrA, belongs to the American-standard low-alloy high-strength structural steel plate family per ASTM A633/A633M.
The "633" in the designation is the standard number, not a strength value; the grade designation letters A through E indicate different strength and toughness combinations (grades C, D and E provide improved low-temperature toughness).
A633A has the characteristics of high strength, high toughness and good welding performance, and is a better material in industrial production.
2. Delivery Condition and Steelmaking
ASTM A633 requires the plates to be delivered in the normalised condition (normalising at a suitable temperature, followed by air cooling). A633A steel is a killed steel: compared with rimmed steel, killed steel is less prone to bubble and sand-hole defects. The steel is refined by oxygen converter or electric furnace, both freely selectable, with fine-grain practice. Production thickness is typically 8-150 mm.
3. Typical Chemical Composition and Mechanicals
| Item | Typical value (Gr.A) |
|---|---|
| Carbon (max) | 0.18% |
| Manganese | 1.00-1.35% |
| Phosphorus / Sulfur (max) | 0.04% / 0.05% |
| Silicon | 0.15-0.50% |
| Yield strength (min) | 290 MPa (42 ksi) |
| Tensile strength | 430-570 MPa (62-83 ksi) |
| Elongation (min) | 23% in 200 mm / 25% in 50 mm |
Typical values per ASTM A633/A633M; impact requirements vary by grade and supplementary specification.
4. Applications
A633A has higher yield strength and toughness than ordinary structural carbon steel, and also offers certain corrosion resistance and fatigue resistance. It is often used in hydraulic machinery, construction machinery, mining machinery, or for structural parts requiring welding. Confirm the applicable grade (A-E) with the design requirements.
5. Stock Reference (Indicative, tonnes)
| Size (mm) | Edges | Weight (t) |
|---|---|---|
| 18.4 x 1810 x 12150 | Four cut edges | 6.352 |
| 9 x 2140 x 6190 | Four cut edges | 10.936 |
| 50 x 1700 x 9800 | Four cut edges | 39.234 |
| 46 x 3150 x 10310 | Four cut edges | 11.727 |
| 6 x 1950 x 6000 | Four cut edges | 0.551 |
| 21 x 2460 x 5170 | Four cut edges | 2.097 |
| 34 x 1800 x 12300 | Four cut edges | 5.909 |
| 35 x 1915 x 12300 | Four cut edges | 6.287 |
| 30 x 1900 x 6100 | Four cut edges | 2.729 |
Inventory data are indicative; confirm availability and certification with the supplier.
Frequently Asked Questions
Q1. Does "633" mean yield strength 633 MPa?
No - 633 is the standard number; Gr.A yield is ≥290 MPa (42 ksi).
Q2. What delivery condition is required?
Normalised, per ASTM A633.
Q3. What are the mechanicals of Gr.A?
Yield ≥290 MPa, tensile 430-570 MPa, elongation ≥23%/25% (typical).
Q4. Which grade for low-temperature service?
Grades C, D and E provide improved low-temperature toughness; select per the design requirement.
Looking for high‑strength structural steel plate with guaranteed normalized delivery and reliable weldability?
GNEE Steel stocks A633 Gr.A in a wide range of thicknesses (8–150 mm) with full mill traceability, tensile/impact reports, and dimensional certificates. Our inventory list above is only a snapshot – we can also source non‑stock sizes and grades (B, C, D, E) upon request to match your design requirements for low‑temperature toughness.
👉 Send us your target size, grade, and quantity – we'll reply with a firm offer within 4 hours. For first‑time trial orders, we provide free cut samples from our stock so you can perform your own welding and mechanical verification before full‑scale production.
Let GNEE Steel be your steady supplier for hydraulic, construction, and mining machinery projects. Contact us now – we're ready to discuss your delivery schedule and certification needs.
Disclaimer:
The technical data, chemical composition, mechanical properties, stock sizes, and application examples provided in this article are for general reference only. Actual product performance may vary depending on plate thickness, heat‑treatment practice, and specific mill production. All values should be verified against the applicable ASTM A633/A633M standard edition and the actual mill test certificates supplied with each order. Stock availability and dimensions are indicative and subject to prior sale; please confirm current inventory and certification with our sales team.
