ASTM A570
Basic Info
The ASTM A570 standard specifies the standard specifications for hot-rolled carbon steel plates and strips for general purposes. These steels are commonly used in buildings, bridges, vehicles, and other structures, with moderate strength and workability. This standard covers the chemical composition, mechanical properties, and dimensional requirements of steel, ensuring that the product meets quality standards and can meet general engineering requirements.
Characteristics
Structural Steel: ASTM A570 steel is primarily used as a structural material in the construction industry for various applications such as bridges, buildings, and other structures.
Good Weldability: This steel grade exhibits good weldability, allowing for ease of fabrication and assembly using common welding techniques such as arc welding, gas welding, and resistance welding.
Multiple Grades: ASTM A570 steel is available in multiple grades, including Grade 30, Grade 33, and Grade 36, each offering different levels of strength and ductility to meet specific design requirements.
Cost-effective: It provides a cost-effective solution for structural projects due to its availability, ease of fabrication, and moderate strength characteristics.
Corrosion Resistance: While not inherently corrosion resistant like some stainless steels, ASTM A570 steel can be coated or painted to enhance its corrosion resistance in aggressive environments, extending its service life in outdoor applications.
ASTM A570 Data Sheet
Steel Grade
Dimensions and Tolerances
Equivalent Steel Grades
Chemical Composition
Mechanical Properties
Fabrication and Welding
ASTM A36 vs. ASTM A570 Steel Comparison
Steel Grade
ASTM A570 Grade 30
- Low strength, suitable for general structural applications with minimal requirements for mechanical properties.
ASTM A570 Grade 33
- Moderate strength, suitable for structural applications requiring moderate strength and improved formability.
ASTM A570 Grade 36
- High strength, suitable for structural applications requiring higher strength and improved weldability compared to Grade 33.
Dimensions and Tolerances
Shape
- Plates, sheets, strips, and structural sections
Width
- Up to 48 inches (1219 mm)
Thickness
- 1/4 inch (6.35 mm) to 1 1/2 inches (38.1 mm)
Length
- Up to 480 inches (12,192 mm)
Tolerance Width
- Over 48 inches (1219 mm) to 60 inches (1524 mm): ±1/32 inch (±0.79 mm)
- Over 60 inches (1524 mm): ±1/16 inch (±1.59 mm)
Tolerance Length
- Over 8 feet (2438 mm) to 10 feet (3048 mm): ±1/8 inch (±3.18 mm)
- Over 10 feet (3048 mm) to 12 feet (3658 mm): ±1/4 inch (±6.35 mm)
Flatness
- As specified in ASTM A6/A6M
Surface Finish
- As specified in ASTM A6/A6M
Equivalent Steel Grades
United States
- Equivalent Grade: ASTM A36
- Standard: ASTM A36
- Notes: Widely used structural steel grade with similar mechanical properties to ASTM A570.
United Kingdom
- Equivalent Grade: BS 4360:43A/B
- Standard: BS 4360
- Notes: British standard equivalent for structural steel with comparable strength and ductility.
Japan
- Equivalent Grade: JIS G3101 SS400
- Standard: JIS G3101
- Notes: Japanese standard equivalent for general structural steel widely used in construction.
Germany
- Equivalent Grade: DIN 17100 St37-2
- Standard: DIN 17100
- Notes: German standard equivalent for structural steel with similar properties to ASTM A570.
Chemical Composition
Carbon (C): 0.25% max
Manganese (Mn): 0.90% max
Phosphorus (P): 0.04% max
Sulfur (S): 0.05% max
Mechanical Properties
ASTM A570 Grade 30:
- Tensile Strength: 330 MPa min
- Yield Strength: 205 MPa min
- Elongation in 8 inches: 20% min
- Elongation in 2 inches: 23% min
ASTM A570 Grade 33:
- Tensile Strength: 360 MPa min
- Yield Strength: 230 MPa min
- Elongation in 8 inches: 20% min
- Elongation in 2 inches: 23% min
ASTM A570 Grade 36:
- Tensile Strength: 400 MPa min
- Yield Strength: 250 MPa min
- Elongation in 8 inches: 20% min
- Elongation in 2 inches: 23% min
Fabrication and Welding
Cutting:
- Method: Mechanical cutting methods such as sawing, shearing, or flame cutting.
- Guidelines: Use proper cutting techniques and avoid excessive heat input to prevent material degradation.
- Notes: Proper preheating may be required for thicker sections to prevent internal stresses and distortion.
Forming:
- Method: Perform cold forming operations such as bending and rolling.
- Guidelines: Use a press brake or similar equipment to avoid deformation and excessive strain hardening.
- Notes: Avoid hot forming operations that can lead to reduced toughness and increased susceptibility to cracking.
Machining:
- Method: Conventional machining techniques such as drilling, milling, and turning.
- Guidelines: Employ sharp tools and appropriate coolants to minimize tool wear and hardening.
- Notes: Preheat the workplace if necessary to reduce machining forces and assist tool life.
Welding:
- Method: Shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), gas metal arc welding (GMAW), and flux-cored arc welding (FCAW).
- Guidelines: Select the appropriate process based on material thickness and required mechanical properties.
- Notes: Choose welding processes that minimize heat input and prevent cracking.
Preheating:
- Method: Preheat before welding as per the required specifications.
- Guidelines: Preheat metal to prevent cold cracking and ensure good weldability. Follow welding procedure specifications (WPS).
- Notes: Preheat temperature depends on material thickness and other welding parameters.
Welding Consumables:
- Method: Use consumables with matching or slightly higher strength than the base metals.
- Guidelines: Select consumables based on applicable welding codes and material compatibility.
- Notes: Ensure proper storage to avoid moisture contamination and degradation of performance.
Post-Weld Heat Treatment (PWHT):
- Method: Perform PWHT if required to restore mechanical properties.
- Guidelines: PWHT is necessary for thicker sections or critical areas to relieve residual stresses.
- Notes: PWHT may be necessary to prevent cracking in highly restrained joints.
ASTM A36 vs. ASTM A570 Steel Comparison
Chemical Composition:
ASTM A36 Steel:
- Carbon (C): 0.25% max
- Manganese (Mn): 0.80–1.20%
- Phosphorus (P): 0.04% max
- Sulfur (S): 0.05% max
ASTM A570 Steel:
- Carbon (C): 0.25% max
- Manganese (Mn): 0.90% max
- Phosphorus (P): 0.05% max
- Sulfur (S): 0.05% max
Mechanical Properties:
ASTM A36 Steel:
- Tensile Strength: 400–550 MPa
- Yield Strength: 250 MPa min
- Elongation: 20% min in 8 inches
ASTM A570 Steel:
- Tensile Strength: 400–550 MPa
- Yield Strength: 205 MPa min (Grade 30)
- Elongation: 20% min in 8 inches
Comparison Summary
Chemical Composition: Both ASTM A36 and ASTM A570 have similar maximum carbon content but may differ slightly in manganese content.
Mechanical Properties: Both steels have comparable tensile strength, but ASTM A36 generally has higher yield strength compared to ASTM A570 Grade 30. However, specific grades of ASTM A570 may have higher strengths.
Applications: ASTM A36 is commonly used for general structural purposes, while ASTM A570 is often used for specific structural applications where moderate strength and formability are required.
