SA573 Grade 65 and Grade 70 are high-strength, structural carbon steel plates under ASTM/ASME standards, known for improved toughness, used in heavy construction and tanks; Grade 70 offers higher strength (70-90 ksi tensile) than Grade 65 (around 400-490 MPa tensile), with both requiring good notch toughness, making them suitable for welded applications needing enhanced mechanical properties.
Mechnical property for SA573 Grade 65 mild steel
| Grade | C | Mn | P | S | Si | Nb | V |
| SA573Gr.65 | ≤0.24 | 0.85-1.20 | ≤0.035 | ≤0.04 | 0.15-0.40 | - | - |
Mechnical property for SA573 Grade 70 mild steel
|
Yield strength (≥Mpa) |
Tensile strength (Mpa) |
Elongation in ≥,% |
|
|
290 |
485-620 |
200mm |
50mm |
|
18 |
21 |
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Chemical composition for SA573 Grade 65 carbon steel (Heat Analysis Max%)
| Grade | Thickness | Yield Strength |
Tensile Strength |
Elongation | Charpy V Impact Test | ||
| Degree | Energy 1 | Energy 2 | |||||
| SA573Gr.65 | mm | Min Mpa | Mpa | Min % | - | J | J |
| 5＜t≤300 | 240 | 450-530 | 20 | ||||
Chemical composition for SA573 Grade 70 carbon steel (Heat Analysis Max%)
|
Main chemical elements composition of SA573 Grade 70 |
|||||
|
Thickness(mm) |
C |
Si |
Mn |
P |
S |
|
T≤13 |
0.27 |
0.15-0.40 |
0.85-1.20 |
0.035 |
0.04 |
|
13<T |
0.28 |
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Key Differences & Similarities
Standard: Both fall under ASTM A573/ASME SA573, specifying structural quality, fully killed, fine-grain steel.
Strength: Grade 70 is stronger, with higher tensile strength (70-90 ksi or 485-620 MPa) and yield strength (around 42 ksi or 290 MPa) compared to Grade 65.
Toughness: Both are designed for improved notch toughness, crucial for applications in cold weather or where impact is a concern, like storage tanks.
Applications: Used in general structural work, heavy machinery, welded construction, and storage tanks, often requiring specific Charpy impact tests.
