ASTM A515 Gr.65 Breaking Strength & Specs

The breaking strength (ultimate tensile strength) of ASTM A515 Grade 65 steel is 450–585 MPa (65,000–85,000 psi). This pressure-vessel quality carbon steel plate is designed for intermediate and higher temperature service, with a minimum yield strength of 240 MPa (35,000 psi, thickness dependent). It combines moderate tensile strength, good ductility and weldability, making it suitable for industrial plants and moderate-pressure applications.

Important Clarification: Impact Toughness

ASTM A515 plates are specified for elevated-temperature service and do not carry a Charpy V-notch impact guarantee. Where low-temperature impact toughness is required (e.g., -20 °C or -45 °C), specify ASTM A516 instead. This page previously attributed A516's -20 °C impact testing to A515 - that is incorrect and is corrected here.

Mechanical Properties (Reference)

Chemical Composition (Reference, t ≤ 50 mm)

Welding and Comparison with Q345R

A515 Gr.65 has excellent weldability by SMAW, GMAW and FCAW; thicker plates may require preheating. Compared with Q345R: Q345R has higher yield strength (≥345 MPa) and lower carbon equivalent (easier welding), while A515 Gr.65 follows US/ASTM practice and is widely recognized in international boiler applications; Grade 65 is more cost-effective than Grade 70 where very high strength is unnecessary. Applications: steam boilers, pressure vessels, heat exchangers, moderate-pressure storage tanks in power, petrochemical and chemical plants. A515 Gr.65 is not suitable for cryogenic service.

Common Applications:

Steam boilers and pressure vessels

Heat exchangers

Moderate-pressure storage tanks in industrial, petrochemical, and power plants

1. Can A515 Grade 65 be machined or formed?
Yes, ASTM A515 Grade 65 can be cut, rolled, or machined using standard industrial equipment. Its good ductility and moderate strength allow safe shaping into pressure vessels, tanks, and boilers. Care must be taken to avoid excessive deformation, and proper tooling ensures smooth edges and consistent thickness for reliable industrial fabrication.

2. What is ASTM A515 Grade 65?
ASTM A515 Grade 65 is a low-alloy carbon steel plate widely used for pressure vessels and industrial boilers. It combines moderate tensile strength, ductility, and excellent weldability, making it suitable for industrial applications under moderate pressure and temperature. It is commonly applied in power plants, petrochemical, and chemical industries.

3. How does A515 Grade 65 differ from Grade 70?
Grade 65 has slightly lower tensile and yield strength compared to ASTM A515 Grade 70 but offers similar ductility, toughness, and weldability. It is more cost-effective, making it ideal for moderate-pressure applications where extremely high strength is unnecessary. Grade 65 also provides adequate cold-temperature performance for most industrial boiler and pressure vessel requirements.

4. Can A515 Grade 65 be used for cryogenic applications?
No, ASTM A515 Grade 65 is not optimized for extremely low temperatures such as cryogenic service. For cryogenic or sub-zero applications, steels like A516 Grade 70 are preferred due to superior low-temperature impact toughness. Grade 65, however, performs safely at moderate low temperatures (-20°C), making it suitable for most standard industrial pressure vessels.

5. What are common applications of A515 Grade 65?
A515 Grade 65 is primarily used in steam boilers, pressure vessels, heat exchangers, and moderate-pressure tanks. It is widely applied in power generation, petrochemical, and chemical industries, offering a balance of strength, ductility, and weldability. Its moderate toughness ensures safe operation under industrial pressures and moderate temperature conditions.

6. What is the tensile strength of A515 Grade 65?
The tensile strength of ASTM A515 Grade 65 ranges from 415–520 MPa, depending on plate thickness. This provides adequate resistance to internal pressure and stress in industrial boilers, heat exchangers, and storage tanks. Its mechanical properties allow it to withstand normal service loads while maintaining ductility and structural integrity over long operational periods.

7. Is protective coating required?
Protective coating is recommended in corrosive environments to prevent rust and extend the service life of A515 Grade 65 steel. Options include painting, epoxy lining, or galvanizing, depending on exposure. In standard dry or indoor applications, bare steel is usually sufficient, but coatings improve durability, reduce maintenance costs, and enhance long-term operational safety.