What is A572 Grade 42?
A572 Grade 42 is a high-strength, low-alloy structural steel defined in ASTM A572. It has a minimum yield strength of 42 ksi (290 MPa) and tensile strength of 60–80 ksi (415–550 MPa). Known for good weldability, toughness, and formability, it is commonly used in bridges, buildings, construction equipment, and structural components requiring moderate high strength.
1. Chemical Composition (Typical Values, %)
| Element | C (max) | Mn | P (max) | S (max) | Si |
|---|---|---|---|---|---|
| A572 Grade 42 | 0.21 | ≤ 1.35 | 0.040 | 0.050 | ≤ 0.40 |
2. Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength | 42 ksi (290 MPa) |
| Tensile Strength | 60–80 ksi (415–550 MPa) |
| Elongation (A5) | 18–21% |
| Density | 7.85 g/cm³ |
What is A572 Grade 50?
A572 Grade 50 is a high-strength, low-alloy (HSLA) structural steel specified in the ASTM A572 standard.
It provides a minimum yield strength of 50 ksi (345 MPa), higher than Grade 42, while maintaining excellent weldability, toughness, and formability.
It is widely used in bridges, building structures, cranes, truck frames, and heavy construction components.
1. Chemical Composition (Typical Values, %)
| Element | C (max) | Mn | P (max) | S (max) | Si | Cu (min, optional) |
|---|---|---|---|---|---|---|
| A572 Grade 50 | 0.23 | ≤ 1.35 | 0.040 | 0.050 | ≤ 0.40 | 0.20 |
2. Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength (min.) | 50 ksi (345 MPa) |
| Tensile Strength | 65–90 ksi (450–620 MPa) |
| Elongation (A5) | 18–21% |
| Density | 7.85 g/cm³ |
What is the advantage of them?
A572 Grade 42 offers better weldability, easier forming, and higher ductility because of its lower strength level.
The reduced yield strength (42 ksi vs 50 ksi) means it is less prone to cracking during welding, easier to bend, and more forgiving for fabrication. It is also typically lower cost and suitable for structures that do not require the higher strength of Grade 50.
Summary Table
| Feature | A572 Grade 42 Advantage | Compared With | Reason |
|---|---|---|---|
| Weldability | Better, lower crack risk | Grade 50 | Lower carbon & strength |
| Formability | Easier bending & shaping | Grade 50 | Higher ductility |
| Ductility | Higher | Grade 50 | Lower yield strength |
| Cost | Usually cheaper | Grade 50 | Less alloying required |
| Tolerance for fabrication errors | More forgiving | Grade 50 | Softer, easier to adjust |
GNEE Steel also supplies a variety of high-strength steel plates, such as A514 Grade F, A572 Grade 50, A588 Grade A, S355JR, S690Q, SS400, S690QL, Q345B, Q345E, etc. If you want to know more about other types of steel plates, you can call the consultation hotline at +8615824687445 or send an email to info@gneesteels.com. You are welcome to consult us, and we are very willing to answer your questions.
