ASTM B166
ASTM B166 Basic Info
ASTM A689 is a specification that covers the standard requirements for carbon and alloy steel bars for springs, designed for various industrial applications. These steel bars are typically hot-wrought and subjected to heat treatment to achieve desired mechanical properties, such as tensile strength, yield strength, and hardness. ASTM A689 outlines specific chemical composition limits, heat treatment conditions, and dimensional tolerances to ensure consistent quality and performance of the finished products. This standard serves as a crucial guideline for manufacturers and users in the spring industry to produce and select appropriate steel bars that meet their specific requirements for spring applications.
Characteristics of ASTM B166
- High Temperature Resistance: Alloys specified in ASTM B166, such as Inconel 600 and Inconel 601, exhibit excellent resistance to high temperatures, maintaining their mechanical properties even at elevated temperatures.
- Corrosion Resistance: These alloys are highly resistant to corrosion, including oxidation, making them suitable for use in harsh and corrosive environments such as chemical processing and marine applications.
- Good Mechanical Properties: ASTM B166 specifies the mechanical properties of these alloys, which include high tensile strength, yield strength, and excellent fatigue resistance, providing structural integrity in demanding conditions.
- Versatility: The standard covers a variety of forms including rod, bar, wire, and forged bars, offering versatility in manufacturing processes and applications.
- Chemical Stability: Inconel alloys conforming to ASTM B166 maintain their properties in a wide range of chemical environments, making them suitable for use in aggressive chemical processing industries.
- Creep Resistance: These alloys also exhibit good creep resistance, which is crucial for components exposed to high temperatures for extended periods, such as turbine blades and exhaust systems in aerospace applications.
ASTM B166 Data Sheet
Steel Grade
Dimensions and Tol.
Equivalent Steel Grades
Chemical Composition
Mechanical Properties
Fabrication and Welding
Steel Grade
Inconel 600:
Alloy Composition: Nickel-Chromium-Iron Alloy
Inconel 601:
Alloy Composition: Nickel-Chromium-Iron Alloy
Inconel 625:
Alloy Composition: Nickel-Chromium-Molybdenum Alloy
Inconel 718:
Alloy Composition: Nickel-Chromium-Molybdenum-Columbium Alloy
Inconel X-750:
Alloy Composition: Nickel-Chromium Alloy with Aluminum and Titanium
Dimensions and Tol.
Round Rod:
- Size Range: 0.187″ to 4″ (4.76 mm to 101.6 mm)
- Tolerances:Diameter: ±0.005″ (±0.13 mm)
Square Bar:
- Size Range: 0.187″ to 2″ (4.76 mm to 50.8 mm)
- Tolerances:Width: ±0.005″ (±0.13 mm)
Hexagonal Bar:
- Size Range: 0.250″ to 1.5″ (6.35 mm to 38.1 mm)
- Tolerances:Across Flats: ±0.010″ (±0.25 mm)
Wire:
- Size Range: 0.002″ to 0.156″ (0.05 mm to 3.96 mm)
- Tolerances:Diameter: ±0.0005″ (±0.013 mm)
Equivalent Steel Grades
Germany:
Equivalent Steel Grade: DIN 2.4816 (NiCr15Fe)
Japan:
Equivalent Steel Grade: JIS NCF 600 (NiCr15Fe)
China:
Equivalent Steel Grade: GB/T NS312 (NiCr15Fe)
United Kingdom:
Equivalent Steel Grade: BS NA 14 (NiCr15Fe)
Chemical Composition
Inconel 600:
- Nickel (Ni): 72.0 min
- Chromium (Cr): 14.0–17.0
- Iron (Fe): 6.0–10.0
- Carbon (C): 0.15 max
- Manganese (Mn): 1.0 max
- Silicon (Si): 0.5 max
- Sulfur (S): 0.015 max
- Copper (Cu): 0.5 max
Inconel 601:
- Nickel (Ni): 58.0 min
- Chromium (Cr): 21.0–25.0
- Iron (Fe): Balance
- Carbon (C): 0.10 max
- Manganese (Mn): 1.0 max
- Silicon (Si): 0.5 max
- Sulfur (S): 0.015 max
- Aluminum (Al): 1.0–1.7
Inconel 625:
- Nickel (Ni): 58.0 min
- Chromium (Cr): 20.0–23.0
- Iron (Fe): 5.0 max
- Carbon (C): 0.10 max
- Manganese (Mn): 0.50 max
- Silicon (Si): 0.50 max
- Sulfur (S): 0.015 max
- Aluminum (Al): 0.40 max
- Molybdenum (Mo): 8.0–10.0
- Niobium (Nb): 3.15–4.15
- Titanium (Ti): 0.4 max
Inconel 718:
- Nickel (Ni): 50.0–55.0
- Chromium (Cr): 17.0–21.0
- Iron (Fe): Balance
- Carbon (C): 0.08 max
- Manganese (Mn): 0.35 max
- Silicon (Si): 0.35 max
- Sulfur (S): 0.015 max
- Aluminum (Al): 0.20–0.80
- Molybdenum (Mo): 2.8–3.3
- Niobium (Nb): 4.75–5.50
- Titanium (Ti): 0.65–1.15
Inconel X-750:
- Nickel (Ni): 70.0 min
- Chromium (Cr): 14.0–17.0
- Iron (Fe): 5.0–9.0
- Carbon (C): 0.08 max
- Manganese (Mn): 1.00 max
- Silicon (Si): 0.50 max
- Sulfur (S): 0.01 max
- Copper (Cu): 0.50 max
- Aluminum (Al): 0.40–1.00
- Molybdenum (Mo): 0.50 max
- Titanium (Ti): 2.25–2.75
- Phosphorus (P): 0.015 max
Mechanical Properties
Inconel 600:
Tensile Strength (Annealed): 80 ksi (550 MPa)
Tensile Strength at 1000°F (540°C): 70 ksi (485 MPa)
Yield Strength (0.2% offset, Annealed): 30 ksi (205 MPa)
Elongation (Annealed): 30%
Inconel 601:
Tensile Strength (Annealed): 80 ksi (550 MPa)
Tensile Strength at 1000°F (540°C): 70 ksi (485 MPa)
Yield Strength (0.2% offset, Annealed): 30 ksi (205 MPa)
Elongation (Annealed): 30%
Inconel 625:
Tensile Strength (Annealed): 120 ksi (827 MPa)
Tensile Strength (Solution Annealed): 130 ksi (896 MPa)
Yield Strength (0.2% offset, Annealed): 70 ksi (483 MPa)
Yield Strength (0.2% offset, Solution Annealed): 70 ksi (483 MPa)
Elongation (Annealed): 30%
Elongation (Solution Annealed): 30%
Inconel 718:
Tensile Strength (Annealed): 135 ksi (930 MPa)
Tensile Strength (Age Hardened (H1150)): 180 ksi (1240 MPa)
Yield Strength (0.2% offset, Annealed): 70 ksi (482 MPa)
Yield Strength (0.2% offset, Age Hardened (H1150)): 150 ksi (1035 MPa)
Elongation (Annealed): 30%
Elongation (Age Hardened (H1150)): 12%
Inconel X-750:
Tensile Strength (Annealed): 130 ksi (896 MPa)
Tensile Strength (Age Hardened (H1150)): 180 ksi (1240 MPa)
Yield Strength (0.2% offset, Annealed): 60 ksi (414 MPa)
Yield Strength (0.2% offset, Age Hardened (H1150)): 150 ksi (1035 MPa)
Elongation (Annealed): 30%
Elongation (Age Hardened (H1150)): 14%
Fabrication and Welding
Inconel 600 (ASTM B166):
Hot Forming: Temperature range: 1600-2250°F (870-1230°C). Avoid working below 1700°F (927°C). Rapid quench after hot forming to avoid sensitization.
Cold Forming: Can be cold formed using standard methods.
Machining: Use water-based coolants for cutting operations. Avoid sulfur-based oils.
Welding: Use Inconel filler metal 600 or Inconel filler metal 625 for high-temperature applications. Preheat and post-weld heat treatment may be required.
Inconel 601 (ASTM B166):
Hot Forming: Temperature range: 1600-2250°F (870-1230°C). Avoid working below 1700°F (927°C). Rapid quench after hot forming to avoid sensitization.
Cold Forming: Can be cold formed using standard methods.
Machining: Use water-based coolants for cutting operations. Avoid sulfur-based oils.
Welding: Use Inconel filler metal 601. Preheat and post-weld heat treatment may be required.
Inconel 625 (ASTM B166):
Hot Forming: Temperature range: 1800-2150°F (982-1177°C). Avoid working below 1700°F (927°C). Rapid quench after hot forming to avoid sensitization.
Cold Forming: Can be cold formed using standard methods.
Machining: Use water-based coolants for cutting operations. Avoid sulfur-based oils.
Welding: Use Inconel filler metal 625. Preheat and post-weld heat treatment may be required.
Inconel 718 (ASTM B166):
Hot Forming: Temperature range: 1700-2100°F (927-1149°C). Rapid quench after hot forming to avoid sensitization.
Cold Forming: Can be cold formed using standard methods.
Machining: Use water-based coolants for cutting operations. Avoid sulfur-based oils.
Welding: Use Inconel filler metal 718. Preheat and post-weld heat treatment may be required.
Inconel X-750 (ASTM B166):
Hot Forming: Temperature range: 1800-2150°F (982-1177°C). Avoid working below 1600°F (871°C). Rapid quench after hot forming to avoid sensitization.
Cold Forming: Can be cold formed using standard methods.
Machining: Use water-based coolants for cutting operations. Avoid sulfur-based oils.
Welding: Use Inconel filler metal 718. Preheat and post-weld heat treatment may be required.
Best Practices for Welding ASTM B166 Alloys
Welding ASTM B166 alloys requires careful consideration of the material’s properties to ensure a strong and reliable bond. These nickel-chromium-iron alloys, including Inconel 600 and Inconel 601, are known for their excellent corrosion resistance and high-temperature strength. Here are some best practices for welding ASTM B166 alloys:
- Pre-Weld Preparation: Before welding, ensure that the surfaces to be welded are clean and free of contaminants such as oil, grease, and oxides. Use a suitable solvent or cleaning method to remove any impurities.
- Use Compatible Filler Metals: Select filler metals that match the composition of the base metal. Common choices include ERNiCr-3 (Inconel 82) and ERNiCrMo-3 (Inconel 625) for welding Inconel 600 and 601, respectively. These filler metals help maintain the alloy’s corrosion resistance and mechanical properties.
- Controlled Heat Input: ASTM B166 alloys are sensitive to heat input during welding. Use low heat input techniques such as TIG (Tungsten Inert Gas) welding with a low amperage setting to minimize the heat-affected zone (HAZ). This reduces the risk of microstructural changes and maintains the material’s properties.
- Preheat and Post-Weld Heat Treatment: For thick sections or critical applications, preheating the base metal can help reduce thermal stresses and improve weldability. Post-weld heat treatment (PWHT) may be necessary to relieve residual stresses and restore mechanical properties. Follow the recommended heating and cooling rates per ASTM specifications.
- Shielding Gas: When using gas tungsten arc welding (GTAW), ensure a suitable shielding gas such as argon or argon-helium mixtures to protect the weld from atmospheric contamination, which can cause porosity and affect corrosion resistance.
- Avoiding Distortion: ASTM B166 alloys are prone to distortion due to their high-temperature properties. Use proper fixturing and welding sequence to minimize distortion, especially in complex or large weldments.
- Quality Control: Inspect welds using non-destructive testing (NDT) methods such as dye penetrant testing or radiographic testing to ensure integrity. Follow ASTM standards for testing and inspection procedures.
