1. ASTM A709 is a standard issued by the American Society for Testing and Materials (ASTM). Its full name is "Standard Specification for Structural Steel for Bridges", which is the standard for structural steel for bridges.
2. Scope
The ASTM A709 standard is mainly applicable to carbon steel and high-strength low-alloy structural steel for bridges. According to the yield strength and its application occasion, it is divided into multiple levels, such as A709 Gr36, A709 Gr50, A709 Gr100, etc. Different levels have different mechanical properties such as yield strength.
3. Corresponding steel plate type
A709 - 50W steel plate
This is a low-alloy high-strength structural steel plate with excellent performance, which is produced and inspected according to the ASTM A709 standard.
Mechanical properties: yield strength is between 345 - 520MPa, tensile strength must be greater than or equal to 485MPa, and elongation has clear requirements, but the specific values need to refer to the material book.
Weather resistance: Due to the addition of alloy elements, it has excellent weather resistance under harsh climatic conditions. A dense rust layer can be formed on the surface of the steel plate to prevent further corrosion inside and extend the service life. It is suitable for steel structures exposed to the atmosphere for a long time, such as bridges and buildings. 1.
Welding and processing performance: It has good welding performance and can be connected and assembled by common welding methods; it also has good processing performance, such as cutting and bending, which can meet the manufacturing needs of complex structures.
Chemical composition: It contains carbon (C), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), copper (Cu), nickel (Ni), chromium (Cr), titanium (Ti), vanadium (V) and other elements. The content range of some elements is: carbon (C) ≤0.23%, silicon (Si) 0.15 - 0.40%, manganese (Mn) 0.80 - 1.50%, phosphorus (P) ≤0.030%, sulfur (S) ≤0.030%.
Size specifications: The size specifications are diverse and can be customized according to needs. Common thickness ranges from a few millimeters to tens of millimeters, the width is generally 2000-3200mm, and the length is between 6000-13000mm.
4. A709 Gr50 steel plate
It is also an American standard bridge steel plate, which implements ASTM A709/A709M standard.
Thickness tensile performance: Z-direction performance of three levels of Z15/Z25/Z35 can be customized.
Chemical composition: carbon content C≤0.23, silicon content Si≤0.40, manganese content Mn≤1.35, phosphorus content P≤0.04, sulfur content S≤0.05, nickel content Ni≤0.32.
Mechanical properties: yield strength ≥345MPa, tensile strength is usually high, and the specific value may vary depending on the production batch and heat treatment process. In addition, it also has excellent toughness and wear resistance, can withstand impact loads and vibration, and has stable and reliable performance under low temperature conditions3.
Processing performance: It has excellent weldability and toughness, and is suitable for complex processing such as cutting, bending, and welding. When cutting, you can choose the appropriate cutting method according to the thickness of the steel plate, such as CNC plasma cutting, CNC laser cutting, or CNC flame cutting3.
5. A709-50T-2 steel plate
It belongs to high-rise building steel, that is, steel plate for high-rise building structure. 50 is the grade in the ASTM A709/A709M standard, which is equivalent to the structural steel for bridges with a yield strength of ≥345MPa. This grade is equivalent to Q345q4 in the Chinese GB/T 714 standard.
6. Application field
Steel plates produced based on the ASTM A709 standard are widely used in the field of bridge construction because of their high strength, good toughness, weather resistance, weldability and other excellent properties. They can also be used in some high-rise buildings and other structures that require high steel performance.
