Technical specifications and application area of ASTM A890 duplex castings
This specification defines the requirements for cast duplex stainless steels (austenitic-ferritic class) supplied by EV Group China. These alloys are characterized by a synergy of high mechanical performance and enhanced resistance to localized and general corrosion, achieved through precise chemical composition and strict adherence to heat treatment regimes.
The microstructure of these steels provides for a ferrite phase content in the range of 30% to 60%, with the remainder being austenite. The choice of a specific steel grade for a project implementation should be based on an analysis of operating conditions, required strength characteristics, and the corrosive aggressiveness of the environment.
EV Group China notes that metric and inch units of measurement in the standard are independent systems. To avoid non-compliance with technical requirements, it is not recommended to combine values from different measurement systems when designing products.
The standard was developed within the framework of international WTO standardization principles, which guarantees the unification of product quality in the global metal market.
Recommendations for placing an order with EV Group China
To ensure the correct execution of an order for cast products compliant with the ASTM A890 standard, the following technical documentation must be provided:
- Detailed drawings of the castings indicating all geometric parameters and tolerances.
- Precise designation of the specification, the required steel grade, and the current release year of the standard.
- Specifications for additional options according to clause 9.1 of the standard.
- A list of additional quality control requirements and acceptance criteria for the finished products.
Production technology
The entire range of products supplied by EV Group China is manufactured using the electric arc melting method. To achieve the required metal purity, a refining technology using Argon-Oxygen Decarburization (AOD) is employed, which minimizes the content of harmful impurities.
Heat treatment regimes
All castings undergo mandatory heat treatment, the parameters of which are strictly regulated by the requirements listed in the table below:
| Steel Grade | Heat treatment temperature, °C | Cooling method |
|---|---|---|
| ASTM A890 Grade 1A | 1040 (minimum) | Rapid cooling in water or air |
| ASTM A890 Grade 4A | 1080 (minimum) | Rapid cooling |