Nimonic® 75, Alloy N75, 2.4630, 2.4951 - nickel alloy

Alloy N75, 2.4630, UNS N06075, Nimonic® 75, Haynes® 75 Alloy - nickel alloy according to DIN 17752, ISO 9722, ASTM

Alloy N75, Nimonic® 75 – description

Alloy N75 (UNS N06075, Nimonic® 75, W.Nr 2.4951 and 2.4630) is a solution-strengthened Ni-Cr alloy with controlled additions of titanium and carbon. First introduced in 1940s, It remains a basic heat-resistant alloy used in low-stress gas turbine and industrial applications up to 650°C. The alloy is readily formed and fabricated using conventional techniques.

Applications

Gas turbines, welded rings, casings in aerospace, and various fabricated parts in general industrial heating uses.

Physical and mechanical properties

Room temperature physical properties:

• Density: 8.37 g/cm³
• Melting temperature: 1340-1380 °C
• Specific heat capacity: 461 J

High-temperature Coefficient of thermal expansion, from 20°C to:

• 100°C: 11.0 μm/m⋅K
• 200°C: 12.7 μm/m⋅K
• 300°C: 13.4 μm/m⋅K
• 400°C: 13.9 μm/m⋅K
• 500°C: 14.3 μm/m⋅K
• 600°C: 15.0 μm/m⋅K
• 700°C: 15.4 μm/m⋅K
• 800°C: 16.5 μm/m⋅K
• 900°C: 17.1 μm/m⋅K
• 1000°C: 18.2 μm/m⋅K

Thermal conductivity:

• 20°C: 11.7 W/m · K
• 400°C: 18.6 W/m · K
• 600°C: 22.7 W/m · K
• 700°C: 24.7 W/m · K
• 800°C: 26.5 W/m · K
• 900°C: 28.4 W/m · K
• 1000°C: 30.1 W/m · K

Electrical resistivity:

• 20°C: 1.09 μΩ·m
• 200°C: 1.12 μΩ·m
• 400°C: 1.17 μΩ·m
• 600°C: 1.15 μΩ·m
• 700°C: 1.15 μΩ·m
• 800°C: 1.15 μΩ·m
• 900°C: 1.15 μΩ·m
• 1000°C: 1.16 μΩ·m

Young's modulus:

• 20°C: 221 GPa
• 100°C: 216 GPa
• 200°C: 210 GPa
• 300°C: 203 GPa
• 400°C: 197 GPa
• 500°C: 190 GPa
• 600°C: 181 GPa
• 700°C: 173 GPa
• 800°C: 165 GPa
• 900°C: 153 GPa
• 1000°C: 140 GPa

Mechanical properties of 2.4951 sheets according to DIN 17750:

• Yield strength: >240 MPa
• Tensile strength: >650 MPa
• Elongation: >25 %
• Hardness HBW: <230

Mechanical properties of 2.4951 sheets according to DIN 17750 (temper designation F65):

• Yield strength: >240 MPa
• Tensile strength: >650 MPa
• Elongation: >25 %
• Hardness HBW: <230

Mechanical properties of 2.4951 bars according to DIN 17752 (temper designation F65):

• Yield strength: >240 MPa
• Tensile strength: >650 MPa
• Elongation: >25 %
• Hardness HBW: <230

Mechanical properties of 2.4951 bars according to DIN 17752 (temper designation F65):

• Yield strength: >240 MPa
• Tensile strength: >650 MPa
• Elongation: >25 %
• Hardness HBW: <230

High-temperature strength properties of annealed Haynes® 75 alloy sheets:

• 20°C:
  • Yield strength: 407 MPa
  • Tensile strength: 792 MPa
  • Elongation: 31 %
• 540°C:
  • Yield strength: 363 MPa
  • Tensile strength: 726 MPa
  • Elongation: 27 %
• 650°C:
  • Yield strength: 275 MPa
  • Tensile strength: 473 MPa
  • Elongation: 32 %
• 760°C:
  • Yield strength: 152 MPa
  • Tensile strength: 286 MPa
  • Elongation: 75 %
• 870°C:
  • Yield strength: 68 MPa
  • Tensile strength: 139 MPa
  • Elongation: 90 %
• 980°C:
  • Yield strength: 31 MPa
  • Tensile strength: 66 MPa
  • Elongation: 91 %

Stress-rupture strength of Haynes® 75 alloy:

• 650°C, 10h: 185 MPa
• 650°C, 100h: 130 MPa
• 650°C, 1 000h: 83 MPa
• 705°C, 10h: 110 MPa
• 705°C, 100h: 70 MPa
• 705°C, 1 000h: 47 MPa
• 760°C, 10h: 66 MPa
• 760°C, 100h: 41 MPa
• 760°C, 1 000h: 26 MPa
• 815°C, 10h: 40 MPa
• 815°C, 100h: 26 MPa
• 815°C, 1 000h: 15 MPa
• 870°C, 10h: 25 MPa
• 870°C, 100h: 14 MPa
• 870°C, 1 000h: 8,3 MPa

Corrosion behaviour

Nimonic® alloy 75 has very good heat-resistance up to 600-650°C.

Static high-temperature oxidation - good resistance. Average weight loss after 100 hours at given temperature with continuous heating:

• 800°C: 0.55 mg/cm²
• 900°C: 1.18 mg/cm²
• 950°C: 4.00 mg/cm²
• 1000°C: 6.66 mg/cm²
• 1100°C: 8.92 mg/cm²

Cyclic high-temperature oxidation - good resistance. Average weight loss after 100 hours at given temperature with cooling down to room temperature every 24 hours:

• 900°C: 2.25 mg/cm²
• 950°C: 4.61 mg/cm²
• 1000°C: 4.68 mg/cm²
• 1100°C: 14.1 mg/cm²

Weldability

Alloy 75 can be welded by MMA, TIG, MIG and submerged-arc processes. It can also be brazed, soldered and weld by electron beam and oxyacetylene. The piece should be in the annealed condition before welding, but a small amount of cold work is tolerable. Post-weld heat treatment is usually unnecessary, although a stress-relieve could be good for caustic soda, fluosilicates and some mercury salts applications.

Heat treatment, working and machining

Recommended working and heat treatment parameters:

• Hot working: 1220-950 °C; air cool / water quench
• Annealing: 1050 °C; air cool

Annealing - anneal bars for 30-60 minutes, anneal sheets for 5-10 minutes. Air cooling. When welding sheets, anneal 5-10 minutes, air cool, then optionally anneal for 10 minutes and air cool again.

Cold working - the good ductility of alloy N75 in the annealed state allows significant cold working without rupture.

Machining - readily machinable. Similar in mechanical properties to austenitic stainless steels. Best machined in cold-drawn or cold-drawn and stress-relieved conditions.

• Rough turning of the alloy in annealed condition, high speed steel:
  • Feed: 0.76 mm/rev
  • Cutting speed: 8 m/min
• Finishing turning of the alloy in annealed condition, high speed steel:
  • Feed: 0.2 mm/rev
  • Cutting speed: 10 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 BS HR 5, BS HR 504, DIN 17752, ASD-STAN prEN 2306-001, ISO 9723-25
• Sheets and plates according to BS HR 203, DIN 17750, ASD-STAN prEN 2293-001, ASD-STAN prEN 2302-001, ASD-STAN prEN 2411-001, ISO 6208
• Pipes according to BS HR 403, DIN 17751, ASD-STAN prEN 2294-002, ISO 6207
• Parts according to DIN 17742, ASD-STAN prEN 2308-002

Replacements, equivalents and other designations:

Nimonic® 75, Haynes® 75 alloy, Alloy N75, 2.4951, NiCr20Ti, 2.4630, 2HR 504, ANC 8 BS 3146, HR 203 BS, HR 403, NW6621, ChN78T, El435, SAE J467, DMV 675, UNS N06075, Nimonic® alloy 75, NI-P91HT