Nickel Alloy Seamless Tube ASTM B622 Hastelloy C22 UNS N06022 For Reactors Vessels

1. Applications

ASTM B622 C22 (Hastelloy C-22) seamless tubes are used in extreme environments requiring corrosion resistance, high-temperature stability, and mechanical reliability:

• Chemical Processing:

Reactors, distillation columns, and piping for sulfuric, hydrochloric, and nitric acid handling.

Heat exchangers in chloride-rich cooling systems (e.g., seawater or brine).

• Oil & Gas:

Downhole tubing, subsea umbilicals, and valves in sour gas (H₂S) environments.

Flare stacks and condensers in refineries.

• Pharmaceuticals:

Sterile bioreactors and CIP/SIP (clean-in-place/steam-in-place) systems.

• Nuclear:

Fuel reprocessing equipment exposed to nitric acid and radioactive waste storage.

• Power Generation:

Gas turbine combustion liners, geothermal brine pipes, and boiler tubes.

• Unique Use Cases:

Marine propeller shafts, aerospace hydraulic lines, and semiconductor fabrication tools.

2. Strength

• Mechanical Properties (Per ASTM B622):

Tensile Strength: ≥ 690 MPa (100 ksi)

Yield Strength: ≥ 310 MPa (45 ksi)

Elongation: ≥ 45% (ensures ductility for forming/welding).

Hardness: ≤ 100 HRB (Rockwell B scale).

• Material Strengths:

(1). Corrosion Resistance:

Resists pitting, crevice corrosion, and stress corrosion cracking (SCC) in chlorides, sulfides, and mixed acids (e.g., HCl + FeCl₃).

Performs in both oxidizing (e.g., HNO₃) and reducing (e.g., H₂SO₄) environments.

(2). Temperature Performance:

Retains strength from cryogenic (-196°C) up to 600°C (1112°F).

Resists oxidation and carburization in high-heat settings.

(3). Pressure Integrity:

Seamless construction allows use in high-pressure systems (e.g., hydraulic lines, HPHT oil wells).

3. Making Process

• Material Selection:

Raw alloy UNS N06022 (Ni-Cr-Mo-W) is vacuum-melted to ensure purity and homogeneity.

• Hot Forming:

Extrusion: Heated billets are forced through a die to form hollow tubes.

Rotary Piercing: Solid billets are pierced with a mandrel to create seamless tubes.

• Cold Working:

Cold drawing or rolling improves dimensional accuracy and surface finish.

• Heat Treatment:

Solution annealing at 1120–1175°C (2050–2150°F) followed by rapid quenching to dissolve secondary phases and restore corrosion resistance.

• Finishing:

Pickling in nitric/hydrofluoric acid to remove oxide layers.

Polishing (optional) for hygienic or high-purity applications.

4. Quality Control:

Non-Destructive Testing (NDT): Eddy current, ultrasonic, or hydrostatic testing to detect flaws.

Certification: Mill test reports (MTRs) verify compliance with ASTM B622 for chemistry, mechanical properties, and dimensions.

Key Advantages of Seamless Construction:

No welds = no weak points, ideal for high-pressure/temperature applications.

Uniform grain structure enhances corrosion resistance and fatigue life.