ASTM B444 UNS N06625 is a specification for nickel-chromium-molybdenum-columbium alloys (UNS N06625) seamless and welded tubes. 

The properties of ASTM B444 UNS N06625 tubes:

• 1. Density: 8.44 g/cm3

• 2. Melting range: 1290-1350°C or 2350-2460°F

• 3. Tensile strength: ≥ 760 MPa or ≥ 110,200 psi

• 4. Yield strength: ≥ 345 MPa or ≥ 50,000 psi

• 5. Elongation: ≥ 30%

• 6. Hardness: ≤ 217 Brinell or ≤ HBW 220

• 7. Thermal conductivity: 12.4 W/m·K or 85.7 BTU-in/hr·ft²·°F

• 8. Electrical conductivity: 94.2% IACS

• 9. Corrosion resistance: Excellent resistance to corrosion in various environments including seawater, acid, and alkaline solutions, and oxidizing and reducing environments.

ASTM B444 UNS N06625 Steel tubes different heat-treated conditions:

Grade 1 (annealed)—Material is normally employed in service temperatures up to 1100°F (593°C).

Grade 2 (solution annealed)—Material is normally

employed in service temperatures above 1100°F (593°C) when resistance to creep and rupture is required.

ASTM B444 UNS N06625 Steel tube Hydrostatic Test

Each pipe or tube with an outside diameter 1⁄8 in. (3 mm) and larger and with wall thickness of 0.015 in. (0.38 mm) and over shall be tested in accordance with Specification B 829. 

Hydrostatic or Nondestructive Electric Test—Each pipe or tube shall be subjected to either the hydrostatic test or to the nondestructive electric test. The type of test to be used shall be at the option of the manufacturer, unless otherwise specifified in the purchase order.

These properties make ASTM B444 UNS N06625 tubes suitable for use in various applications including chemical processing, power generation, oil and gas industries, and aviation and aerospace industries.