In terms of material selection, it is usually a compromise between toughness and strength. The choice depends on applications, machinability, and weldability. As for ASTM A105, it is a plain carbon steel, while ASTM A105N represents normalized carbon steel. The heat treatment improves the mechanical properties of the component.
What is ASTM A105?
ASTM A105 is a specification for forged carbon steel piping components, such as flanges, fittings, and valves, used in pressure systems. It is designed for use in high-temperature and high-pressure applications. The material is characterized by its good mechanical properties and weldability, making it suitable for various industrial applications, including oil and gas, chemical processing, and power generation.
What is ASTM A105N?
ASTM A105N is similar to A105 but includes an “N,” indicating that the material has undergone normalization—a heat treatment process that refines the grain structure and relieves internal stresses. This treatment enhances the mechanical properties of the steel, making A105N particularly suitable for applications where improved strength and performance under stress are required, especially in low-temperature environments.
ASTM A105 VS A105N
| Feature | ASTM A105 | ASTM A105N |
| Material Type | Flanges, Fittings, Valves | Flanges, Fittings, Valves |
| Heat Treatment | Not normalized | Normalized |
| Mechanical Properties | Standard properties | Enhanced properties |
| Applications | General pressure systems | Pressure systems with high stress |
| Usage Temperature | Suitable for higher temps | Suitable for low temperatures |
| Internal Stress | May retain internal stress | Reduced internal stress |
ASTM A105 Chemical Composition
| Element | C | Si | Mn | P | S | Cu | Cr | Ni | Mo | V |
| Composition, % | ≤0.35 | 0.10~0.35 | 0.60～1.05 | ≤0.035 | ≤0.040 | ≤0.40 | ≤0.30 | ≤0.40 | ≤0.12 | ≤0.08 |
NOTE:
- For each reduction of 0.01 % below the specified carbon maximum (0.35 %), an increase of 0.06 % manganese above the specified maximum (1.05 %) will be permitted up to a maximum of 1.35 %.
- The sum of copper, nickel, chromium, molybdenum and vanadium shall not exceed 1.00 %.
- The sum of chromium and molybdenum shall not exceed 0.32 %.
Mechanical Requirements
| Element | Tensile Strength, min: | Min. Yield Point: | Reduction of area, min: | Hardness, HB, max |
| ASTM A105 | 70,000 psi (485 MPa] | 36,000 psi [250 MPa] | 30% min | 187 |
More information about ASTM A105 VS 105N:
https://www.quora.com/How-do-the-ASTM-A105-and-the-ASTM-A105N-piping-applications-differ
