What is the yield strength of SA709 Grade 50?
While its strength is the same as other 50 ksi steels, A709 Grade 50's value is in its guaranteed toughness and code compliance for bridge construction, making it the legally and technically required specification-not just an equivalent-for structural members in highway bridges in the United States.
SA572 Grade 50 Products Description
SA572 Grade 50 is a High-Strength Low-Alloy (HSLA) Columbium-Vanadium structural steel, known for excellent strength-to-weight ratio, minimum 50 ksi yield strength, good weldability, and increased atmospheric corrosion resistance, making it a versatile "workhorse" for heavy-duty applications like bridges, buildings, and infrastructure components where lighter, stronger material is needed.
The minimum yield strength of ASTM A709 Grade 50 is 50 ksi (345 MPa).
This is identical to the yield strength of SA572 Grade 50. The key difference is that A709 Grade 50 is a bridge-specific version of the same base material, governed by the AASHTO (American Association of State Highway and Transportation Officials) bridge design code. It includes mandatory impact toughness requirements and, in its weathering variant (Grade 50W), provides significantly enhanced atmospheric corrosion resistance.
Quick Specification Breakdown:
| Property | A709 Grade 50 (Non-Weathering) | A709 Grade 50W (Weathering) | Note |
|---|---|---|---|
| Yield Strength (min) | 50 ksi (345 MPa) | 50 ksi (345 MPa) | Identical minimum. |
| Tensile Strength (min) | 65 ksi (450 MPa) | 65 ksi (450 MPa) | |
| Key Feature | Mandatory impact toughness for bridge safety. | Same as Grade 50, plus weathering resistance for unpainted exposure. | The "W" denotes weathering. |
| Governing Code | AASHTO LRFD Bridge Design Specifications | AASHTO LRFD Bridge Design Specifications | Must be used for US highway bridges. |
What is A709 grade 50W steel?
ASTM A709-50W is a standard specification for structural steel primarily in the fabrication of steel bridges. ASTM A709-50W covers high strength, low allow steel structural shapes, plates and bars.
What is ASTM A709 steel grade?
The ASTM A709 is the Standard Specification for Structural Steel for Bridges and encompasses carbon, high-strength low-alloy, and quenched and tempered alloy steels used as structural plates in the construction of bridges. SSAB offers the following five grades of A709; 36, 50, 50W, HPS 50W and HPS 70W.
What is the difference between ASTM A572 Grade 50 and ASTM A709 Grade 50?
A572 Grade 50: Used in a wide range of structural applications, including buildings, transmission towers, equipment, and general construction. It's not specifically optimized for bridges. A709 Grade 50: Primarily used for bridge construction and other structures where enhanced toughness and weldability are critical.
What is the yield strength of ASTM A709 grade 50?
Grade 50 steel of this specification requires a minimum yield strength of 50 ksi. Used as structural members in bridge building or for similar structures.
What is the difference between ASTM A36 and A709?
ASTM A709 grade 36 is a bridge material wherein carbon adds to the strength and hardenability of the steel. A36 has less than0. 30% carbon and thus, do not possess high hardenability. ASTM A709 grade 36 steel plate has improved corrosion resistance and can be used in outdoor applications.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
