ASTM A522 Type 1 forged flanges are specialized 9% nickel alloy steel forgings designed specifically for cryogenic service conditions (as low as -196°C), classified under Type I of the ASTM A522 standard. Combining the excellent low-temperature toughness provided by high nickel content with forging technology, they serve as critical pressure-containing components in deep-cryogenic applications such as liquefied natural gas (LNG).
Material definition and applicable standards
Project | Specific Description |
Full name of the standard | ASTM A522/A522M “Forged or Rolled Flanges, Pipe Fittings, Valves and Components of 8% and 9% Nickel Alloy Steels for Low Temperature Applications”.
Material types: Type I (with a nominal nickel content of 9%) and Type II (with a nominal nickel content of 8%).
Applicable temperature | Type I is designed for a service temperature range of -196°C to 121°C.
Maximum section thickness | The standard imposes clear restrictions on the maximum section thickness of forgings:
Double normalizing + tempering state: Maximum 3 inches [75mm].
Quenched + tempered state: Maximum 5 inches [125mm].
Chemical composition and mechanical properties
Since the ASTM A522 Type I is highly similar to the 06Ni9D grade specified in the domestic standard NB/T 47009, the following data can be used as a reference for the material properties:
Chemical composition (wt%)
Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Nickel (Ni) | Phosphorus (P) | Sulfur (S)
Content | ≤0.08 | 0.15 – 0.35 | 0.30 – 0.80 | 8.50 – 10.0 | ≤0.008 | ≤0.004 |
Mechanical properties (refer to 06Ni9D, quenched + tempered state, thickness ≤ 125mm)
Performance indicators | Typical values |
Tensile strength | 680 – 840 MPa |
Yield strength (Rp0.2) | ≥ 550 MPa |
Strain (A) | ≥ 18% |
Impact energy (KV2 @ -196°C) | ≥ 60 J (average value)
Key requirements for forged flanges
The manufacturing of forged flanges must strictly adhere to the standards, and the key points include:
Heat treatment process: The process of quenching + tempering (Q+T) or double normalizing + tempering must be adopted to achieve the required low-temperature toughness.
2. Rigorous testing: Stretch tests and Schmidle impact tests must be conducted as per the regulations to verify the mechanical properties.
3. Forge grade: For materials such as 06Ni9D, the standard usually requires that each piece or a sample of the forged part undergoes tensile, impact and ultrasonic testing. The specific level is determined according to the design specifications.
ASTM A522 TYPE 1 forged flanges is a special pressure-bearing component designed for use in a -196°C cryogenic environment. Its core value lies in the outstanding low-temperature toughness and strength provided by the 9% nickel content. Enfe Pipeline Technology (Cangzhou) Co., Ltd. has the qualification and relevant certifications to produce such material flanges.
