The core differences between A105 and A105N valves lie in their heat treatment process and performance characteristics. The specific differences are as follows:
1. Heat Treatment Differences
A105 valves
Using ordinary carbon steel forgings (C ≤ 0.35%, Mn 0.6-1.05%),
No heat treatment is required, maintaining the original as-forged properties, with a hardness of ≤ HB187.
A105N valves
The material composition is identical to A105 (ASTM standards do not differ in composition),
Adding normalizing treatment (N stands for Normalizing) refines the grain size and improves mechanical strength.
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2. Improved Mechanical Properties
Strength Enhancement:
Normalizing A105N valves achieve higher tensile strength and significantly better high-pressure impact resistance than ordinary A105.
Improved Temperature Resistance:
Normalizing eliminates internal stresses, increasing the upper operating temperature limit of the A105N valve by approximately 50°C (up to 600°C).
3. Application Scenario Differentiation
A105 Applicable Operating Conditions
Low-temperature, low-pressure, non-corrosive media (water, oil, low-pressure steam);
Conventional industrial piping (e.g., plant water supply systems).
A105N Applicable Operating Conditions
High-temperature, high-pressure environments (PN 320 main steam piping in thermal power plants);
Highly corrosive media (chemical reactor inlets and outlets, with alloy sealing surfaces);
Harsh environments such as offshore platforms (salt spray corrosion resistance).
4. Operation and Maintenance Differences
Welding Requirements:
A105N valves require local heat treatment after welding to restore performance, while standard A105 valves do not require this.
Testing Standards:
A105N valves must be accompanied by an impact toughness test report (impact energy ≥ 34J at -29°C) before shipment.