What is the difference between A106 and A105?
The key differences lie in the standard type and application field: A105 is a standard for carbon steel forgings used in piping components (e.g., valves, flanges), while A106 is a standard for seamless steel pipes. Although both are low-carbon steels, A105 has higher mechanical strength (tensile strength ≥485 MPa), and A106-B is equivalent to China's 20 steel, making it suitable for high-temperature piping systems.
Differences in Standards and Applications
A105 (ASTM A105): Specifically designed for forgings in piping components, such as valves and flanges, and must meet forging requirements under both Chinese and American standards.
A106 (ASTM A106): Pertains to seamless steel pipes, including grades A106-A and A106-B, with the latter being equivalent to China's 20 steel, primarily used in high-temperature piping systems in industries like oil and chemical.
Comparison of Chemical Composition and Mechanical Properties
Chemical Composition: Both are low-carbon steels (carbon content ≤0.35%), but A105 has stricter controls over trace elements like manganese (Mn 0.6-1.05%), sulfur, and phosphorus to ensure forging performance.
Mechanical Properties:
A105: Tensile strength ≥485 MPa, yield strength ≥250 MPa, hardness ≤HB187. It is stronger than 20 steel but has weaker resistance to stress corrosion cracking.
A106-B: Mechanical properties are close to 20 steel, with a tensile strength of ~415 MPa and yield strength of ~240 MPa, making it suitable for medium- and low-pressure piping.
Which is better ASTM A105N or ASTM A216 WCB?
Material Difference
A105N Valves: Made of carbon steel, specifically forged steel from ASTM A105 (Series A).
WCB Valves: Also carbon steel, but refers to cast steel (WCB/WCC) under ASTM A216.
Forming Process Difference
A105N Valves: Forged via plastic deformation, refining internal microstructure for better mechanical properties and uniform grain distribution.
WCB Valves: Cast via liquid metal molding, which may cause segregation/defects but excels in complex shapes where forging is impractical.
Performance Difference
A105N Valves: Superior quality, higher impact resistance, and better ductility/toughness than WCB cast steel. Preferred for critical components.
WCB Valves: Includes cast carbon steel, low-alloy steel, and special steel. Ideal for complex, high-strength parts where forging is unfeasible.
Recommendation:
Choose A105N valves for high-demand projects (e.g., high-pressure systems).
Opt for ASTM A216 WCB valves for general applications with lower strength requirements.
contact us for A105N Valve date sheet