ASTM A573/A573M is a standard specification for structural carbon steel plates intended for applications requiring improved notch toughness compared to ordinary carbon steels like
A36. It is commonly used in low-temperature service where impact resistance is critical, yet full alloy steel specifications are unnecessary.
The standard covers three grades with increasing strength and toughness levels:
Grade 58 (yield strength ≥ 220 MPa / 32 ksi)
Grade 65 (yield strength ≥ 240 MPa / 35 ksi)
Grade 70 (yield strength ≥ 290 MPa / 42 ksi)
ASTM A573/A573M Product Performance Features:
| Property |
Grade 58 |
Grade 65 |
Grade 70 |
| Tensile Strength (MPa) |
400–485 |
450–530 |
485–620 |
| Elongation (200 mm) |
21% min |
18% min |
16% min |
| Charpy V-Notch (20 J @ 20°C) |
Required |
Required |
Required |
| Maximum Thickness (mm) |
200 |
125 |
100 |
The improved toughness of ASTM A573 steel is achieved through controlled manufacturing practices, including fine grain practice (ASTM grain size No. 5 or finer) and fully killed steel with aluminum or silicon deoxidation. These measures significantly reduce the ductile-to-brittle transition temperature, enabling reliable performance at temperatures down to -20°C to -45°C, depending on thickness and grade.
Typical applications include pressure vessel components, storage tanks, bridge components, offshore platforms, and structural members in cold regions. For instance, in oil storage tank fabrication for arctic environments,
A573 grade 70 ensures crack arrest properties that standard A36 cannot guarantee.
In summary, ASTM A573/A573M bridges the gap between ordinary carbon steel and costly nickel-alloyed grades, offering dependable notch toughness at moderate cost.
