ASTM A515 Grade 70 is a carbon‑manganese steel plate designed for moderate‑temperature pressure vessel service. Produced to ASTM A515, it is suitable for fusion welding in boilers and pressure vessels. This grade offers good strength, toughness, and weldability, ensuring reliable performance at elevated temperatures. It is commonly used for pressure vessel components, storage tanks, and boiler parts where consistent operation under moderate pressure and temperature is required.
Chemical Composition of ASTM A515 Grade 70
|
Element |
Product Analysis Max (%) |
Ladle Analysis Max (%) |
|---|---|---|
|
Carbon (C) |
0.30-0.35 |
0.30-0.35 |
|
Manganese (Mn) |
1.30 |
1.20 |
|
Phosphorus (P) |
0.035 |
0.035 |
|
Sulfur (S) |
0.035 |
0.035 |
|
Silicon (Si) |
0.13-0.45 |
0.15-0.40 |
Mechanical Properties of ASTM A515 Grade 70
|
Thickness (mm) |
Yield Strength (Min Mpa) |
Tensile Strength (Mpa) |
Elongation (Min %) |
|---|---|---|---|
|
≤ 200 |
260 |
485-620 |
17 |
|
≤ 50 |
260 |
485-620 |
21 |
Comparison with Other ASTM A515 Grades
|
Property |
A515 Grade 60 |
A515 Grade 65 |
A515 Grade 70 |
|---|---|---|---|
|
Carbon Content (Max %) |
0.24-0.31 |
0.28-0.33 |
0.30-0.35 |
|
Manganese (Max %) |
0.98 |
0.98 |
1.30 |
|
Yield Strength (Min Mpa) |
220 |
240 |
260 |
|
Tensile Strength (Mpa) |
415-550 |
450-585 |
485-620 |
|
Elongation (Min %, 200mm) |
21 |
19 |
17 |
Comparison with ASTM A516 Grades
|
Property |
A515 Grade 70 |
A516 Grade 55 |
A516 Grade 60 |
A516 Grade 65 |
A516 Grade 70 |
|---|---|---|---|---|---|
|
Temperature Service |
Intermediate/High |
Moderate/Low |
Moderate/Low |
Moderate/Low |
Moderate/Low |
|
Carbon Content (Max %) |
0.30-0.35 |
0.18-0.26 |
0.21-0.27 |
0.24-0.29 |
0.27-0.31 |
|
Yield Strength (Min Mpa) |
260 |
205 |
220 |
240 |
260 |
|
Tensile Strength (Mpa) |
485-620 |
380-515 |
415-550 |
450-585 |
485-620 |
|
Elongation (Min %, 200mm) |
17 |
27 |
25 |
23 |
21 |
processing
Melting and Refining: ASTM A515 Grade 70 begins with melting iron ore and scrap steel in a furnace, followed by refining to control carbon, manganese, and other elements. This step ensures the chemical composition meets the standard's requirements for strength and weldability.
Continuous Casting: The molten steel is cast into slabs or blooms using continuous casting equipment. This process helps maintain uniform structure and reduces segregation, providing a solid foundation for consistent mechanical properties in the final plate.
Hot Rolling: The cast slabs are reheated and rolled into plates of the desired thickness. Controlled rolling practices refine the grain structure, improving toughness and strength while ensuring good surface quality.
Heat Treatment (When Required): Depending on thickness and application, some plates may undergo normalizing or stress‑relief annealing. These treatments enhance ductility, reduce internal stresses, and optimize weldability for pressure vessel fabrication.
Descaling and Conditioning: After rolling, the plates are descaled to remove oxide layers and then inspected for surface defects. Conditioning processes such as grinding ensure the material meets the required surface finish and dimensional tolerances.
Testing and Inspection: Plates undergo rigorous testing, including chemical analysis, mechanical property evaluation, ultrasonic inspection, and visual checks. These tests verify compliance with ASTM A515 standards, ensuring reliability for critical pressure vessel use.
applications
Pressure Vessels and Boilers: ASTM A515 Grade 70 is widely used in fabricating pressure vessels, boilers, and heat exchangers. Its good strength and weldability make it suitable for shells, heads, and other components that operate under moderate temperatures and pressures.
Oil and Gas Industry: The material is commonly employed in refineries, gas processing plants, and petrochemical facilities. It is used for process vessels, separators, and storage tanks that handle hydrocarbons and other fluids under moderate service conditions.
Power Generation Equipment: In power plants, it is used for boiler drums, headers, and associated structural parts. Its ability to withstand thermal cycling and maintain integrity at elevated temperatures supports reliable power generation operations.
General Industrial Fabrication: The steel plate is utilized in various industrial applications, including process piping supports, heavy machinery frames, and structural components that require a balance of strength and cost‑effectiveness.
Water and Wastewater Treatment: It is used in tanks, clarifiers, and pressure vessels for water treatment systems. Its durability and resistance to moderate corrosion in water environments make it a practical choice for such infrastructure.
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.
What is the elongation requirement for ASTM A515 Grade 70?
The minimum elongation is 20% in a 2-inch (50.8 mm) gauge length. Elongation measures the material's ductility, indicating its ability to stretch before breaking, which is essential for fabrication and safety.
Can ASTM A515 Grade 70 be cold-formed?
Yes, it can be cold-formed, but proper procedures are needed. Cold forming may increase residual stresses and reduce ductility, so stress relieving heat treatment is often recommended after cold forming to restore properties.
What is the difference between ASTM A515 Grade 60 and Grade 70?
The main difference is tensile and yield strength: Grade 70 has higher minimum tensile (70 ksi vs. 60 ksi) and yield (38 ksi vs. 30 ksi) strengths. Grade 70 is used for more demanding pressure and temperature applications than Grade 60.
Is ASTM A515 Grade 70 corrosion-resistant?
It has moderate corrosion resistance in mild environments but is not highly resistant to severe corrosion (e.g., acidic or salty conditions). Additional protection like painting, galvanizing, or coating is needed for use in corrosive environments.
What is the standard thickness range for ASTM A515 Grade 70 steel plates?
The standard thickness range is typically 3/16 inch (4.76 mm) to 6 inches (152.4 mm). Thicker plates may be available with special orders, but they require stricter quality control and testing to ensure performance.
What is the form of ASTM A515 Grade 70 most commonly supplied in?
It is most commonly supplied as hot-rolled steel plates. Plates are the preferred form for pressure vessels, boilers, and tanks because they can be easily cut, formed, and welded into the required shapes.
What standards govern the production of ASTM A515 Grade 70?
It is governed by the ASTM International standard ASTM A515/A515M, which specifies the requirements for carbon steel plates for pressure vessels used in moderate and high-temperature service.
What is the maximum temperature ASTM A515 Grade 70 can withstand continuously?
It can withstand continuous service temperatures up to 650°F (343°C). At temperatures above this, its tensile strength and creep resistance decrease, potentially leading to equipment failure over time.
Can ASTM A515 Grade 70 be used for cryogenic applications?
No, it is not suitable for cryogenic applications (temperatures below -20°F/-29°C). At cryogenic temperatures, it may become brittle and lose toughness, increasing the risk of fracture. Special cryogenic steels are required instead.