ASTM A516 Grade 70
Carbon Steel ASTM A516 Grade 70
ASTM A516 Grade 70 Carbon Steel is a high-strength carbon steel plate primarily manufactured for pressure vessels, boilers, storage tanks and welded industrial equipment.
ASTM A516/A516M specifies carbon steel plates intended for pressure vessels where good notch toughness, strength and resistance to brittle fracture are required.
Grade 70 is one of the highest-strength commonly specified grades in the ASTM A516 series. It offers an effective combination of high tensile strength, yield strength, toughness, ductility and weldability, making it suitable for demanding industrial applications.
It is widely used in oil & gas facilities, refineries, petrochemical plants, chemical processing plants, power-generation facilities and pressure-vessel manufacturing.
Key Features
- High-strength carbon steel plate
- Designed for pressure-vessel applications
- High tensile strength
- High yield strength
- Good toughness
- Good ductility
- Good weldability
- Good formability
- Suitable for welded fabrication
- Available in various plate thicknesses
- Suitable for demanding industrial environments
- Can be supplied with additional testing and inspection
Specifications
| Specification | Details |
|---|---|
| Grade | ASTM A516 Grade 70 |
| Material | Carbon Steel |
| Standard | ASTM A516/A516M |
| Product | Steel Plate |
| Product Type | Pressure Vessel Plate |
| Tensile Strength | 485–620 MPa |
| Yield Strength | ≥ 260 MPa |
| Weldability | Good |
| Toughness | Good |
| Main Applications | Pressure Vessels, Boilers, Tanks, Process Equipment |
ASTM A516 Grade 70 Plate Dimensions
ASTM A516 Grade 70 plates can be supplied in a wide range of thicknesses, widths and lengths according to standard or project-specific requirements.
Available Supply Forms
- Standard-size plates
- Cut-to-size plates
- Heavy-thickness plates
- Plates cut according to engineering drawings
- Custom dimensions
- Plates prepared for fabrication
The required plate thickness is generally determined by:
- Design pressure
- Design temperature
- Equipment diameter
- Corrosion allowance
- Required mechanical strength
- Construction code
- Service conditions
- Customer specifications
ASTM A516 Grade 70 Chemical Composition
The chemical requirements depend on the applicable ASTM specification, plate thickness and manufacturing conditions.
| Element | Typical / Maximum Requirement (%) |
|---|---|
| Carbon (C) | ≤ 0.28* |
| Manganese (Mn) | ≤ 1.20* |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
| Silicon (Si) | 0.15–0.40 |
| Copper (Cu) | As applicable |
| Nickel (Ni) | As applicable |
| Chromium (Cr) | As applicable |
| Molybdenum (Mo) | As applicable |
| Iron (Fe) | Balance |
*Chemical requirements can vary with plate thickness and the applicable edition of ASTM A516/A516M. The actual composition should always be verified against the applicable standard and the manufacturer’s Mill Test Certificate (MTC).
ASTM A516 Grade 70 Mechanical Properties
| Property | Requirement |
|---|---|
| Tensile Strength | 485–620 MPa |
| Yield Strength | ≥ 260 MPa |
| Elongation | According to plate thickness |
| Charpy Impact | When specified |
Grade 70 provides a higher strength level than ASTM A516 Grades 55, 60 and 65, making it suitable for applications where higher mechanical strength is required.
Toughness and Impact Resistance
ASTM A516 Grade 70 is designed for applications where a combination of strength and good notch toughness is important.
Typical applications include:
- Pressure vessels
- Boilers
- Storage vessels
- Heat exchangers
- Separators
- Oil & gas equipment
- Petrochemical equipment
- Chemical-processing equipment
When required by the purchaser, construction code or operating conditions, Charpy V-Notch impact testing can be specified at the required test temperature.
Physical Properties
Typical physical properties of carbon steel include:
| Property | Approximate Value |
|---|---|
| Density | 7.85 g/cm³ |
| Modulus of Elasticity | ≈ 200 GPa |
| Thermal Conductivity | ≈ 45–55 W/m·K |
| Thermal Expansion Coefficient | ≈ 11–12 × 10⁻⁶ /°C |
| Magnetic Properties | Magnetic |
For engineering calculations, the values specified by the applicable design code should be used.
Corrosion Resistance
ASTM A516 Grade 70 is a carbon steel and does not have the inherent corrosion resistance of stainless steel.
It can be susceptible to:
- Atmospheric corrosion
- Moisture
- Water
- Chlorides
- Marine environments
- Chemical exposure
- Corrosive process fluids
Corrosion Protection Methods
Depending on the application, protection may include:
- Industrial coating systems
- Epoxy coatings
- Internal linings
- Cathodic protection
- Corrosion inhibitors
- Corrosion allowance
For highly corrosive service, alternatives such as stainless steel, alloy steel or clad plate may be considered.
Heat Treatment
Heat-treatment requirements depend on the plate thickness, manufacturing process, applicable specification and project requirements.
Normalizing
Normalizing helps produce a more uniform microstructure and balanced mechanical properties.
Annealing
Annealing can improve ductility and reduce residual stresses.
Normalizing and Tempering
Where required, normalizing and tempering may be used to achieve specific mechanical and toughness requirements.
For pressure-vessel applications, heat treatment should comply with ASTM A516/A516M and the applicable construction code.
Welding
ASTM A516 Grade 70 offers good weldability and is widely used for welded pressure vessels and industrial equipment.
Common Welding Processes
- SMAW
- GTAW / TIG
- GMAW / MIG
- FCAW
- SAW
Welding Applications
- Pressure-vessel shells
- Vessel heads
- Storage tanks
- Boilers
- Heat exchangers
- Process equipment
Depending on plate thickness and the applicable welding code, requirements may include:
- Preheating
- Interpass temperature control
- Qualified welding procedures
- Post-weld heat treatment (PWHT)
Manufacturing Process
ASTM A516 Grade 70 plates are produced using controlled steelmaking and plate-processing operations.
Typical Manufacturing Steps
- Steelmaking
- Continuous casting or ingot production
- Slab preparation
- Hot rolling
- Heat treatment
- Plate cutting
- Surface conditioning
- Dimensional inspection
- Mechanical testing
- Impact testing when specified
- Non-destructive testing when required
- Final inspection and marking
Quality Control and Testing
Quality requirements depend on the project specification, purchaser requirements and applicable construction code.
Common Tests
- Chemical analysis
- Tensile testing
- Yield-strength testing
- Elongation testing
- Charpy impact testing when specified
- Dimensional inspection
- Visual inspection
- Ultrasonic testing (UT)
- Surface inspection
- Heat-treatment verification
- Material traceability
Material Documentation
Depending on project requirements, plates can be supplied with:
- Mill Test Certificate (MTC)
- Chemical analysis report
- Mechanical test results
- Heat-treatment records
- Charpy impact test results when required
- Inspection certificates
- Material traceability documentation
Applications
Oil & Gas Industry
- Pressure vessels
- Separators
- Storage vessels
- Process equipment
- Hydrocarbon-processing equipment
Refineries
- Pressure vessels
- Boilers
- Heat exchangers
- Storage tanks
- Process equipment
Petrochemical Industry
- Reactors
- Process vessels
- Columns
- Pressure equipment
- Industrial tanks
Power Generation
- Boilers
- Pressure vessels
- Storage tanks
- Auxiliary equipment
- Steam-process equipment
Chemical Industry
- Reaction vessels
- Storage tanks
- Pressure equipment
- Process systems
ASTM A516 Grade 70 vs Other Grades
| Property | Grade 55 | Grade 60 | Grade 65 | Grade 70 |
|---|---|---|---|---|
| Tensile Strength | 380–515 MPa | 415–550 MPa | 450–585 MPa | 485–620 MPa |
| Yield Strength | ≥205 MPa | ≥220 MPa | ≥240 MPa | ≥260 MPa |
| Strength Level | Moderate | High | Higher | Highest |
| Typical Application | Pressure Vessels | Pressure Vessels | Pressure Vessels | Pressure Vessels |
Grade 70 can be selected when the design requires a higher mechanical strength level, subject to the applicable design calculations and material requirements.
ASTM A516 Grade 70 in Tunisia, Algeria, Morocco & Libya
ASTM A516 Grade 70 Carbon Steel is suitable for many industrial projects in Tunisia, Algeria, Morocco and Libya, including:
- Pressure-vessel manufacturing
- Storage tanks
- Boilers
- Heat exchangers
- Process equipment
- Oil & gas facilities
- Petrochemical installations
- Chemical-processing plants
Depending on the project and end-user requirements, specifications may reference:
- ASTM A516/A516M
- ASME Section II
- ASME Section VIII
- ASME Section IX for welding qualification
Final material selection should consider design pressure, design temperature, plate thickness, impact requirements, corrosion allowance, welding requirements, heat treatment, inspection requirements and the applicable construction code.
Conclusion
Carbon Steel ASTM A516 Grade 70 is a high-strength pressure-vessel steel plate offering an excellent combination of strength, toughness, ductility and weldability.
With a tensile strength of 485–620 MPa and a minimum yield strength of 260 MPa, Grade 70 provides a higher strength level than ASTM A516 Grades 55, 60 and 65.
It is widely used for pressure vessels, boilers, storage tanks, heat exchangers, process equipment, refineries, petrochemical plants, power-generation facilities, chemical plants and oil & gas projects.
For industrial projects in Tunisia, Algeria, Morocco and Libya, ASTM A516 Grade 70 is an appropriate material option when the requirements for pressure, temperature, strength, toughness, welding, heat treatment, inspection and ASTM/ASME compliance are properly defined.
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