ASTM A105 and ASTM A350 LF2 are both commonly used specifications for carbon steel forgings. While they are similar in many ways, there are some key differences between the two.
1. Chemical Composition:
- ASTM A105: This specification covers carbon steel forgings for piping applications. The chemical composition of A105 includes a maximum carbon content of 0.35%, manganese content of 0.60-1.05%, phosphorus content of 0.035% maximum, sulfur content of 0.040% maximum, and silicon content of 0.10-0.35%.
- ASTM A350 LF2: LF2 is a low-temperature carbon steel grade suitable for use in low-temperature applications. The chemical composition of LF2 includes a maximum carbon content of 0.30%, manganese content of 0.60-1.35%, phosphorus content of 0.035% maximum, sulfur content of 0.040% maximum, silicon content of 0.15-0.30%, and nickel content of 3.3-3.7%.
2. Mechanical Properties:
- ASTM A105: A105 has a minimum tensile strength of 70 ksi (485 MPa) and a minimum yield strength of 36 ksi (250 MPa). It also has a minimum elongation of 22%.
- ASTM A350 LF2: LF2 has a minimum tensile strength of 70 ksi (485 MPa) and a minimum yield strength of 36 ksi (250 MPa). It has a minimum elongation of 22% and a minimum reduction of area of 30%.
3. Application:
- ASTM A105: A105 is commonly used for forged carbon steel piping components such as flanges, fittings, and valves in high-temperature and high-pressure service conditions.
- ASTM A350 LF2: LF2 is primarily used for low-temperature applications, such as cryogenic storage tanks, pressure vessels, and piping systems that operate at temperatures as low as -50°F (-46°C).
4. Impact Testing:
- ASTM A105: Impact testing is not mandatory for A105.
- ASTM A350 LF2: LF2 requires impact testing at -50°F (-46°C) and has specific requirements for minimum absorbed energy values.
It is important to note that the selection between ASTM A105 and ASTM A350 LF2 should be based on the specific requirements of the application, including temperature, pressure, and other factors. Consulting the relevant codes, standards, and engineering specifications is recommended to ensure the correct material selection.
