ASTM B444
ASTM B444 Basic Info
ASTM B444 outlines the characteristics of seamless and welded nickel-chromium-molybdenum-columbium alloys tubes. These tubes exhibit excellent resistance to corrosion and high temperatures, making them suitable for applications in chemical processing, aerospace, and marine engineering. With stringent specifications for dimensions, mechanical properties, and material composition, ASTM B444 ensures the reliability and performance of these tubes in demanding environments.
Characteristics of ASTM B444
- High Temperature Resistance: ASTM B444 materials are designed to withstand high temperatures, making them suitable for applications in environments with extreme heat conditions.
- Corrosion Resistance: These materials exhibit excellent resistance to corrosion, particularly in harsh and corrosive environments such as chemical processing plants and offshore oil rigs.
- Uniformity: ASTM B444 specifies seamless and welded nickel-chromium-iron alloy pipes and tubes, ensuring uniformity in construction and performance.
- Durability: The materials conforming to ASTM B444 standards are known for their durability and reliability, providing long-term performance even in demanding industrial settings.
- Versatility: ASTM B444 materials are versatile and find applications in various industries, including aerospace, marine, pharmaceuticals, and power generation, due to their exceptional mechanical properties and corrosion resistance.
ASTM B444 Data Sheet
Steel Grade
Dimensions and Tol.
Equivalent Steel Grades
Chemical Composition
Mechanical Properties
Fabrication and Welding
Steel Grade
UNS N06625:
Commonly known as Inconel 625, this nickel-chromium-molybdenum alloy offers high strength and corrosion resistance.
UNS N06852:
Known as Alloy 686, this nickel-chromium-molybdenum-tungsten alloy provides exceptional corrosion resistance in aggressive media.
UNS N10276:
Hastelloy C-276, a nickel-molybdenum-chromium alloy, is renowned for its versatility and resistance to various corrosive environments.
Dimensions and Tol.
Round Pipes:
- Dimensions:
Outer Diameter: Up to 8 inches (200 mm)
Wall Thickness: Up to 0.750 inches (19 mm)
- Tolerances:
Permissible Variations in Outside Diameter:
±0.015 inches (0.38 mm) for NPS 1/4 to 1 1/2
±0.030 inches (0.76 mm) for NPS 2 and larger
Outside Diameter and Wall Thickness Tolerances: As specified in ASTM B444
Round Tubes:
- Dimensions:
Outer Diameter: Up to 6 inches (150 mm)
Wall Thickness: Up to 0.375 inches (9.5 mm)
Length: As specified in purchase order
- Tolerances:
Permissible Variations in Outside Diameter: ±0.030 inches (0.76 mm)
Outside Diameter and Wall Thickness Tolerances: As specified in ASTM B444
Length Tolerance: ±1/16 inch (1.6 mm) or ±0.5% of specified length, whichever is greater
Equivalent Steel Grades
United States:
Equivalent Grades: UNS N06625, UNS N06852, UNS N10276
Standard: ASTM B444
Germany:
Equivalent Grades: 2.4856, 2.4602, 2.4819
Standard: DIN EN 10088, DIN EN 10216-5
United Kingdom:
Equivalent Grades: NA21, NA22, NA30
Standard: BS 3074, BS 3075
Japan:
Equivalent Grades: NCF625, NCF686, NCHM276
Standard: JIS G3459, JIS G3463
Chemical Composition
UNS N06625 (Inconel 625):
- Nickel (Ni): 58.0 min
- Chromium (Cr): 20.0 – 23.0
- Iron (Fe): 5.0 max
- Molybdenum (Mo): 8.0 – 10.0
Manganese (Mn): 0.50 max
- Silicon (Si): 0.50 max
- Carbon (C): 0.10 max
- Sulfur (S): 0.015 max
- Phosphorus (P): 0.015 max
- Copper (Cu): 0.50 max
- Titanium (Ti): 0.40 max
- Aluminum (Al): –
UNS N06852 (Alloy 686):
- Nickel (Ni): 52.0 min
- Chromium (Cr): 19.0 – 23.0
- Iron (Fe): 1.0 max
- Molybdenum (Mo): 15.0 – 17.0
- Tungsten (W): 3.0 – 4.4
- Cobalt (Co): 2.5 max
- Manganese (Mn): 0.50 max
- Silicon (Si): 0.50 max
- Carbon (C): 0.020 max
- Sulfur (S): 0.010 max
- Phosphorus (P): 0.015 max
- Copper (Cu): 0.50 max
- Titanium (Ti): 0.40 max
- Aluminum (Al): –
UNS N10276 (Hastelloy C-276):
- Nickel (Ni): 55.0 min
- Chromium (Cr): 14.5 – 16.5
- Iron (Fe): 4.0 – 7.0
- Molybdenum (Mo): 15.0 – 17.0
- Manganese (Mn): 1.0 max
- Silicon (Si): 0.08 max
- Carbon (C): 0.01 max
- Sulfur (S): 0.03 max
- Phosphorus (P): 0.04 max
- Copper (Cu): 0.50 max
- Titanium (Ti): 0.60 max
- Aluminum (Al): 0.35 max
Mechanical Properties
UNS N06625 (Inconel 625):
- Tensile Strength (MPa): 760 min
- Yield Strength (0.2% Offset) (MPa): 345 min
- Elongation (%): 30 min
- Modulus of Elasticity (GPa): 200 min
- Poisson’s Ratio: –
- Impact Strength (J): –
UNS N06852 (Alloy 686):
- Tensile Strength (MPa): 690 min
- Yield Strength (0.2% Offset) (MPa): 275 min
- Elongation (%): 35 min
- Modulus of Elasticity (GPa): 205 min
- Poisson’s Ratio: –
- Impact Strength (J): –
UNS N10276 (Hastelloy C-276):
- Tensile Strength (MPa): 690 min
- Yield Strength (0.2% Offset) (MPa): 310 min
- Elongation (%): 40 min
- Modulus of Elasticity (GPa): 206 min
- Poisson’s Ratio: 0.3
- Impact Strength (J): –
Fabrication and Welding
Machining:
- ASTM B444 materials can be machined using conventional methods, but carbide-tipped tools are recommended to minimize tool wear and achieve smooth finishes.
Forming:
- Cold forming operations such as bending and shaping can be performed on ASTM B444 materials, but it’s essential to avoid excessive deformation to prevent cracking or weakening of the material.
Heat Treatment:
- Heat treatment of ASTM B444 materials may be necessary to achieve desired mechanical properties or relieve residual stresses from fabrication processes. Consult material specifications for specific heat treatment procedures.
Welding:
- Welding of ASTM B444 materials requires careful consideration of matching filler metals and preheating to minimize the risk of cracking and ensure proper fusion. Common welding methods include TIG (Tungsten Inert Gas) welding and electron beam welding. Proper cleaning of surfaces and shielding gas selection are critical to prevent contamination and achieve high-quality welds.
Post-Weld Heat Treatment (PWHT):
- Depending on the grade and application, post-weld heat treatment may be required to restore material properties and relieve residual stresses from welding. Follow specific PWHT procedures recommended for the grade of ASTM B444 material being welded.
