A516 Grade 70 is a carbon steel plate specification developed for use in pressure vessels and boilers that operate at moderate to low temperatures. It is part of the ASTM A516 standard, which covers several grades of carbon steel plates designed specifically for service where improved notch toughness is required. This grade is known for its good strength, ductility, and weldability, making it suitable for fabricating tanks, heat exchangers, and other pressure-containing equipment. The steel is typically produced with fine-grained microstructure to enhance toughness and is often supplied in normalized condition to ensure consistent mechanical properties across different thicknesses. Its applications span industries such as oil and gas, petrochemical, and power generation, where reliable performance under pressure is essential.
Yield/Tensile Strength
|
Metric |
Imperial |
|
|
Tensile Strength, Ultimate |
482 – 620 MPa |
70 – 90 ksi |
|
Tensile Strength, Yield |
262 MPa |
38 ksi |
|
Elongation |
17 |
17 |
Material Chemistry
|
C |
MN |
P |
SI |
S |
|
0.27 – 0.31% |
1 – 1.7% |
0.025% |
0.15 – 0.40% |
0.025% |
manufacturing and fabrication processes
1. Heat Treatment (Thermal Processing)
Heat treatment is critical for refining grain structure and improving toughness.
Normalizing: Mandatory for plates over 1.5 inches (40 mm) thick. It involves heating the steel to 900°C – 950°C (1650°F – 1740°F) followed by air cooling to refine the grain.
As-Rolled: Plates 1.5 inches (40 mm) or thinner can be supplied in the as-rolled condition unless notch toughness testing is required.
Stress Relieving (PWHT): Typically performed at 540°C – 650°C (1000°F – 1200°F) for roughly one hour per inch of thickness to reduce residual stresses from welding or forming.
2. Welding Procedures
A516 Gr. 70 is categorized as a P-No. 1 Group 2 material, known for excellent weldability.
Processes: Commonly welded using SMAW (Shielded Metal Arc), GMAW/MIG, GTAW/TIG, and SAW (Submerged Arc).
Filler Metals: Use low-hydrogen electrodes such as E7018 to prevent hydrogen-induced cracking (HIC). ER70S-6 is often preferred for gas metal arc welding.
Preheating: Recommended for plates thicker than 1.5 inches (38 mm), typically between 95°C and 200°C (200°F – 400°F) to reduce thermal stress.
3. Fabrication & Machining
Machining: It can be machined using standard methods. Experts suggest using cobalt drill bits or carbide tools with optimal cutting speeds (80-120 SFPM) to manage its tendency to work-harden.
Surface Preparation: Grinding and beveling are used to remove hard scale or oxidation before welding to ensure high-quality surface finishes and weld integrity.
Testing & Inspection: Supplementary requirements often include Ultrasonic Examination (ASTM A435/A578), Charpy V-notch impact testing for low-temperature service, and HIC testing.
applications
1. Oil, Gas & Petrochemical Industry
This is the most dominant sector for A516 Gr. 70 due to its balance of strength and weldability.
Pressure Vessels: Used for separators, columns, reactors, and storage tanks.
Sour Gas Service: When processed to meet NACE MR0175/MR0103 standards, it is used for vessels handling corrosive H2S environments.
LPG/LNG Storage: Used for low-temperature storage tanks (when normalized) to prevent brittle fracture.
2. Power Generation
The material's thermal stability makes it a standard choice for steam-related infrastructure.
Industrial Boilers: Specifically for boiler steam drums, headers, and shells that operate under high internal pressure.
Heat Exchangers: Used in the fabrication of shells and tubesheets for energy recovery systems.
Condensers: Large-scale cooling systems in nuclear and thermal power plants.
3. Transportation and Storage
Used for mobile units that transport hazardous or pressurized materials.
Railroad Tank Cars: For the safe transport of pressurized gases and chemicals over long distances.
Road Tankers: Bulk liquid and gas transport trailers.
Spherical Storage Tanks: Often used for large-scale urban gas storage (Horton Spheres).
4. General Engineering & Construction
Beyond pressure-related uses, its mechanical properties are utilized in heavy fabrication.
Offshore Platforms: Critical structural components for oil rigs and offshore wind turbine foundations.
Bridges and Buildings: Used in heavy-duty structural columns and beams where high-strength carbon steel is required.
Heavy Machinery: Frames for cranes, earth-moving equipment, and large industrial presses.
5. Water and Steam Infrastructure
Penstocks: High-pressure water pipes for hydroelectric power stations.
Calorifiers: Large-scale water heating and storage vessels for commercial or industrial use.
If you have project requirements for A516 Grade 70, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
What is ASTM A516 GR 70?
It is a carbon steel plate standard for pressure vessels, widely used in moderate/low-temperature service. It offers excellent weldability and notch toughness, suitable for boilers and storage tanks.
What is the minimum tensile strength of ASTM A516 GR 70?
Its minimum tensile strength is 70 ksi (485 MPa), with a minimum yield strength of 38 ksi (260 MPa), ensuring good mechanical performance for pressure-bearing applications.
What temperature range is ASTM A516 GR 70 suitable for?
It performs well from -29°C (-20°F) to 343°C (650°F). For lower temps, supplementary toughness tests may be required per project specs.
What are the main chemical components of ASTM A516 GR 70?
Key components: C ≤ 0.31%, Mn 0.79-1.30%, P ≤ 0.035%, S ≤ 0.035%, Si 0.15-0.40%, with trace elements controlled strictly.
Is ASTM A516 GR 70 weldable?
Yes, it has excellent weldability. Common methods like SMAW, GMAW, GTAW work. Preheat/post-heat may be needed based on plate thickness and welding process.
What applications is ASTM A516 GR 70 commonly used for?
It's used in pressure vessels, boilers, storage tanks, pipelines, and petrochemical equipment handling oil, gas, water, and other media.
What is the difference between ASTM A516 GR 60 and GR 70?
GR 70 has higher tensile/yield strength than GR 60. GR 60: min 60 ksi tensile; GR 70: 70 ksi, suited for higher-pressure scenarios.
Does ASTM A516 GR 70 require impact testing?
It depends on service temp. For ≤ -10°C (14°F), Charpy V-notch impact tests are mandatory to ensure sufficient toughness against brittle fracture.
What is the maximum plate thickness for ASTM A516 GR 70?
Standard max thickness is 200 mm (7.87 inches). Thicker plates may need special processing and additional mechanical property verification.
What standards are equivalent to ASTM A516 GR 70?
EN 10028-2 P265GH (Europe) and GB 713 Q345R (China) are approximate equivalents, but technical specs vary; cross-verification is needed.
Can ASTM A516 GR 70 be used in corrosive environments?
It resists mild corrosion but not harsh media. For corrosive conditions, coating, cladding, or upgrading to alloy steels is recommended.