Alloy 601, 2.4851, UNS N06601, Inconel 601 - nickel alloy

Alloy 601, 2.4851, UNS N06601, Inconel® 601 - nickel alloy according to ASTM B166, DIN 17754

Aloy 601, Inconel® 601– description

Alloy 601 is a Ni-Cr-Fe alloy with outstanding high-temperature strength and oxidation resistance.

The alloy can be either solution-treated or annealed. In the solution-treated condition, alloy 601 is used for rupture-limited applications above 540°C. Annealing is best for tensile-limited applications below 540°C.

Applications

Alloy 601 is a general-purpose engineering material, used most notably in petrochemical and refining plants in high-temperature oxidizing environments, where requirements are too demanding for Alloy 800H/HT.

Aloy 601, Inconel® 601 - physical and mechanical properties

Room temperature physical properties:

• Density: 8.1 g/cm³
• Specific heat capacity: 450 J/kg⋅K
• Thermal conductivity: 11.3 W/m⋅K
• Linear expansion coefficient: 14.4-17.7 μm/m⋅K
• Electrical resistivity: 1.19 µΩ⋅m

Coefficient of thermal expansion and temperature (linear):

• 20-100°C: 13.75 μm/m⋅K
• 20-200°C: 14.36 μm/m⋅K
• 20-300°C: 14.58 μm/m⋅K
• 20-400°C: 14.83 μm/m⋅K
• 20-500°C: 15.19 μm/m⋅K
• 20-600°C: 15.62 μm/m⋅K
• 20-700°C: 16.11 μm/m⋅K
• 20-800°C: 16.67 μm/m⋅K
• 20-900°C: 17.24 μm/m⋅K
• 20-1000°C: 17.82 μm/m⋅K

Specific heat and temperature:

• 20°C: 448 J/kg⋅K
• 200°C: 498 J/kg⋅K
• 400°C: 548 J/kg⋅K
• 600°C: 603 J/kg⋅K
• 800°C: 657 J/kg⋅K
• 900°C: 686 J/kg⋅K
• 1000°C: 712 J/kg⋅K

Thermal conductivity and temperature:

• 20°C: 11.2 W/m·K
• 200°C: 14.3 W/m·K
• 400°C: 17.7 W/m·K
• 600°C: 21.0 W/m·K
• 800°C: 24.4 W/m·K
• 900°C: 26.1 W/m·K
• 1000°C: 27.8 W/m·K

Electrical resistivity and temperature:

• 20°C: 1.18 μΩ·m
• 200°C: 1.207 μΩ·m
• 400°C: 1.229 μΩ·m
• 600°C: 1.247 μΩ·m
• 800°C: 1.249 μΩ·m
• 900°C: 1.259 μΩ·m
• 1000°C: 1.262 μΩ·m

High temperature dynamic modulus of elasticity and temperature:

• 20°C: 206.5 GPa
• 200°C: 196.8 GPa
• 400°C: 184.8 GPa
• 600°C: 170.8 GPa
• 800°C: 150.2 GPa
• 900°C: 137.9 GPa
• 1000°C: 124.7 GPa

Mechanical properties of 2.4851 bars according to DIN 17750:

• Yield strength: >205 MPa
• Tensile strength: 550-750 MPa
• Elongation: >30%
• Hardness HB: <220

Tensile properties of hot-drawn bars of annealed (1090°C) Inconel® 601 bars, according to the manufacturer:

• Room temperature
  • Yield strength: 290 MPa
  • Tensile strength: 741 MPa
  • Elongation: 47 %
• 300°C
  • Yield strength: 221 MPa
  • Tensile strength: 674 MPa
  • Elongation: 46 %
• 500°C
  • Yield strength: 203 MPa
  • Tensile strength: 640 MPa
  • Elongation: 45 %

1000h rupture strength of solution-treated (1150°C) Inconel® 601 sheet:

• 650°C: 195 MPa
• 760°C: 60 MPa
• 870°C: 30 MPa
• 980°C: 15 MPa

Temperature stability - alloy 601 retains its mechanical properties despite prolonged exposure to high temperatures. This is shown by the KV impact strength after exposure to high temperatures of a rod made of Inconel® 601 alloy (solution-treated for thermal stability).

• No exposure: 176 J
• 540°C, 100h: 117 J
• 540°C, 1000h: 121 J
• 650°C, 1000h: 127 J
• 700°C, 100h: 129 J
• 820°C, 159h: 159 J
• 870°C, 103h: 159 J

Corrosion behaviour

High-temperature oxidation resistance - exceptional up to 1200°C, thanks to the forming of a protective chromium scale. However, above the temperature of about 1000°C the scale begins to convert into volatile CrC₃, which makes a difference in prolonged exposure. Thus for applications where the temperature exceeds 1000°C for extensive periods of time alloy 214 will be a better choice.

Average metal affected after 1008h of static oxidation test at indicated temperatures:

• 980°C: 0.033 mm
• 1095°C: 0.067 mm
• 1150°C: 0.135 mm
• 1205°C: 0.19 mm

Dynamic oxidation resistance in high-velocity combustion gas stream test results (samples were cycled to less than 260°C once every 30 min):

• 500h, 1090°C:
  • Metal loss: 0.033 mm
  • Maximum metal affected: 0.067 mm with internal nitrides through thickness
• 1000h, 980°C
  • Metal loss: 0.076 mm
  • Maximum metal affected: 0.51

Results of a dynamic oxidation field test in a natural gas-fired furnace. The test took 113 days at 1090-1230°C with frequent cycles to 540°C:

• Metal loss: 0.18 mm
• Maximum metal affected: 0.067 mm with internal nitrides through thickness

Cycling oxidation resistance test lasting for 504h in air-5H₂O at 1100°C:

• Weight change: -11.0 mg/cm²
• Maximum metal affected: 0.067 mm with internal nitrides through thickness

High-temperature carburization - good resistance. Carbon absorption after 100h in H_{2M/sub>-2CH4 at 1000°C equaled 10 mg/cm².}

High-temperature nitridation - good to very good resistance. Alloy 601 is one of the alloys most resistant to high-temperature pure nitrogen and it is very resistant to high-temperature ammonia. Depth of nitride penetration as the results of various nitridation tests are presented below:

• Ammonia 168 h; 650°C: 0.03 mm
• Ammonia 168 h; 980°C: 0.17 mm
• Ammonia 168 h; 1090°C: >0.58 mm
• Pure nitrogen 168 h; 980°C: 1.55 mm
• Pure nitrogen 168 h; 1090°C: 2.79 mm
• Pure nitrogen 168 h; 1204°C: 3.81 mm

High-temperature sulfidation - very poor resistance, due to high nickel content.

High-temperature halogenation - good resistance, which is evident from the weight-loss experienced after the following tests:

• Ar-30Cl₂ 500 h; 400°C: 0.3 mg/cm²
• Ar-30Cl₂ 500 h; 500°C: 3 mg/cm²
• Ar-30Cl₂ 500 h; 600°C: 85-200 mg/cm²
• Ar-30Cl₂ 500 h; 705°C: 215 mg/cm²
• Ar-20O₂-0.25Cl₂ 400 h; 900°C: 20.67 mg/cm²
• Ar-20O₂-0.25Cl₂ 400 h; 1000°C: 124.99 mg/cm²
• HCl 300h; 400°C: 1.58 mg/cm²
• HCl 1000h; 400°C: 1.47 mg/cm²
• HCl 100h; 500°C: 2.57 mg/cm²
• HCl 300h; 500°C: 4.14 mg/cm²
• HCl 1000h; 500°C: 9.38 mg/cm²
• HCl 100h; 600°C: 9.01 mg/cm²
• HCl 300h; 600°C: 19.46 mg/cm²
• HCl 96h; 700°C: 102.5 mg/cm²

Weldability

Basic data: Weldability group 43 (ISO 15608), brazing P-number 111 (ASME section IX).

Selection of welding consumables:

• ENiCrFe-3, ENiCrMo-3 (Electrode); ERNiCr-3, ERNiCrMo-3 (Filler metal)
• Joining with stainless steel: ENiCrFe-2 (Electrode); ERNiCr-3 (Filler metal)
• Joining with low-alloy steel: ENiCrFe-2 (Electrode); ERNiCr-3 (Filler metal)
• Joining with 5-9% Ni steel: ENiCrFe-2 (Electrode); ERNiCr-3 (Filler metal)
• Joining with copper: ENi-1 (Electrode); ERNi-1 (Filler metal)
• Joining with Nickel-copper: ENi-1 (Electrode); ERNi-1 (Filler metal)

Heat treatment, working and machining

The alloy can be hot- and cold-worked and can be either solution-treated (max rupture strength) or annealed (max tensile strength). Recommended working and heat treatment parameters:

• Hot working: 1200-1000 °C
• Solution-treatment: 1100-1200 °C
• Annealing: 1000-1100 °C

During solution treatment or annealing, the piece should be held in the furnace for 30-60 min and then be water quenched or rapid air cooled (continuous annealing) or held for 60-180 min and air-cooled (batch annealing).

Machining - group C, meaning its mechanical properties are similar to austenitic stainless steel. It's best machined in cold-drawn or cold-drawn and stress-relieved conditions.

Recommended turning parameters with high-speed steel:

• Roughing:
  • Feed: 0.25 mm/rev
  • Cutting speed: 15 m/min
• Finishing:
  • Feed: 0.13 mm/rev
  • Cutting speed: 18 m/min

Recommended turning parameters with carbides:

• Roughing:
  • Feed: 0.2 mm/rev
  • Cutting speed: 114 m/min
• Finishing:
  • Feed: 0.1 mm/rev
  • Cutting speed: 130 m/min

Twist drilling with high-speed steel drills recommended parameters:

• Drill diameter: 3.2-4.8 mm
• Feed: 0.05-0.10 mm/rev
• Cutting speed: 8-11 m/min

We deliver this steel alloy as:

• Rod, bar, wire, forging according to ASTM B 166 / ASME SB166. DIN 17752. ISO 9723. DIN 17753. ISO 9724. DIN 17754. ISO 9725. EN10095
• Plates, strips and sheets according to ASTM B 168 / ASME SB168. EN10095
• Seamless and welded pipes according to ASTM B 167 / ASME SB167. ASTM B 751 / ASME SB751. ASTM B 775 / ASME SB 775. ASTM B 829 / ASME SB 829. DIN 17751. ISO 6207

Replacements, equivalents and other designations:

Alloy 601, H06601, HNS3103, 2.4851, NiCr23Fe, BSNA49, NW6601, Ni6601, NiCr23Fe15Al, SNi6601, NCF601, ASTM B 163, ASTM B 166, ASTM B 167, ASTM B 168, ASTM B 474, ASTM B 516, ASME SB163, ASME SB166, ASME SB167, ASME SB516, EMVAC 601, VAT 601, NY 601, Nicrimphy 601, Coralloy 601, Inconel® 601, NRX 601, GL 5 Valbruna