Nickel Alloy GX40NiCrNb45-35 Aged
Heat-treated state
EN 1.4889
Aged = thermally aged / service-exposed
Use the thermally aged or service-exposed state (≈1000 °C, over 1000 h) to assess remaining tube life: secondary carbide and sigma precipitation cut elongation to 2.5 % and raise hardness to 210 HB.
Values for the Aged condition
Other GX40NiCrNb45-35 tempers and conditions
GX40NiCrNb45-35 is listed in 3 conditions; see the grade overview at GX40NiCrNb45-35.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution/diffusion annealed | Use solution/diffusion annealing near 1150 °C with rapid cooling on weldments and complex castings to remove segregation and reach 14 % elongation, at some loss of initial creep strength. | 225 | 455 | 14 | 160 HB | 1.7 % IACS |
Statically (sand/investment) cast, as-cast | Choose static sand or investment casting in the as-cast state for furnace fittings, elbows and supports; equiaxed grains match room-temperature strength but creep life is lower (1050 °C). | 230 | 450 | 8 | 170 HB | 1.7 % IACS |
AgedThis page Thermally aged / service-exposed | Use the thermally aged or service-exposed state (≈1000 °C, over 1000 h) to assess remaining tube life: secondary carbide and sigma precipitation cut elongation to 2.5 % and raise hardness to 210 HB. | 300 | 460 | 2.5 | 210 HB | 1.8 % IACS |
What is GX40NiCrNb45-35 Aged?
GX40NiCrNb45-35 Aged is GX40NiCrNb45-35 heat treated to Aged — use the thermally aged or service-exposed state (≈1000 °C, over 1000 h) to assess remaining tube life: secondary carbide and sigma precipitation cut elongation to 2.5 % and raise hardness to 210 HB. GX40NiCrNb45-35 Aged has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 2.5% and the elastic modulus is 165 GPa (23.9 Msi). GX40NiCrNb45-35 Aged has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 1,330°C (2,426 °F).
Advantages
- Low embodied carbon — 7 kg CO₂/kg, better than 98% of nickel alloy grades
- High service temperature — 1,100°C (2,012 °F), better than 88% of nickel alloy grades
- High electrical conductivity — 1.8 % IACS, better than 82% of nickel alloy grades
Limitations
- Limited formability — 2/100, worse than 99% of nickel alloy grades
- Hard to polish — 45/100, worse than 99% of nickel alloy grades
- Limited ductility — 2.5%, worse than 94% of nickel alloy grades
- Low stiffness — 165 GPa (23.9 Msi), worse than 91% of nickel alloy grades
- Needs corrosion protection — 64/100, worse than 85% of nickel alloy grades
GX40NiCrNb45-35 Aged properties
Typical room-temperature values for GX40NiCrNb45-35 Aged; 22 are specific to this condition. Other listed values are GX40NiCrNb45-35 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
GX40NiCrNb45-35 Aged has a density of 7.9 g/cm³ (0.285 lb/in³), lighter than 92% of nickel alloy grades. It melts at 1,330°C (2,426 °F).
Mechanical15
GX40NiCrNb45-35 Aged has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 78% of nickel alloy grades. Elongation at break is 2.5% and the elastic modulus is 165 GPa (23.9 Msi).
Thermal6
GX40NiCrNb45-35 Aged is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 12 W/m·K (6.93 BTU/hr·ft·°F), better than 65% of nickel alloy grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
GX40NiCrNb45-35 Aged conducts electricity at 1.8 % IACS, better than 82% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is good (64/100), worse than 85% of nickel alloy grades.
Sustainability4
Producing a kilogram of GX40NiCrNb45-35 Aged takes about 95 MJ of energy and emits 7 kg of CO₂ — less than 97% of nickel alloy grades. Typical recycled content is 60%.
Manufacturability8
GX40NiCrNb45-35 Aged's machinability is not recommended (12/100, worse than 86% of nickel alloy grades); weldability poor (25/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with GX40NiCrNb45-35 Aged
Is GX40NiCrNb45-35 easy to machine?
Difficult: the high-carbon eutectic carbides abrade tooling, so use carbide or ceramic inserts, low speed with heavy feed, rigid clamping and generous coolant. Keep the tool cutting under the work-hardened layer.
Can GX40NiCrNb45-35 be welded?
GTAW and SMAW with matching 45Ni-35Cr-Nb filler, 100–200 °C preheat, low heat input and interpass temperature control. On aged tubes taken out of service, machine the carburised layer away before welding.
Can GX40NiCrNb45-35 be formed, bent or molded?
Shaped by casting only, as centrifugally cast tube or sand and investment castings; cold bending and cold forming are not possible. Hot straightening must be done above 1050 °C followed by slow cooling.
What surface finishes work on GX40NiCrNb45-35?
Supplied with the bore bored and the outside diameter turned. Shot blasting, pickling or aluminising can be applied to improve coking and oxidation resistance; anodising does not apply.
GX40NiCrNb45-35 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Chigh carbon provides carbide strengthening | 0.3 – 0.5 | 0.4 |
| Siimproves carburization resistance | ≤ 2 | 1.3 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 33 – 37 | 35 |
| Ni | 43 – 48 | 45 |
| Nbstabilizes MC carbides | 1.2 – 1.8 | 1.5 |
| Fe | balance | — |
GX40NiCrNb45-35 Aged — frequently asked
What is GX40NiCrNb45-35 Aged used for?
GX40NiCrNb45-35 Aged is typically used for ethylene pyrolysis furnace tubes, radiant coil supports and reformer fittings. In short: carburisation-resistant cast tube; nb-stabilised 45/35 casting; petrochemical furnace grade.
What is the yield strength of GX40NiCrNb45-35 Aged?
GX40NiCrNb45-35 Aged has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 78% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is GX40NiCrNb45-35 Aged easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 86% of nickel alloy grades). Difficult: the high-carbon eutectic carbides abrade tooling, so use carbide or ceramic inserts, low speed with heavy feed, rigid clamping and generous coolant. Keep the tool cutting under the work-hardened layer.
Can GX40NiCrNb45-35 Aged be welded?
Not readily — weldability is rated poor (25/100). GTAW and SMAW with matching 45Ni-35Cr-Nb filler, 100–200 °C preheat, low heat input and interpass temperature control. On aged tubes taken out of service, machine the carburised layer away before welding.
What surface finishes work on GX40NiCrNb45-35 Aged?
Supplied with the bore bored and the outside diameter turned. Shot blasting, pickling or aluminising can be applied to improve coking and oxidation resistance; anodising does not apply.
Can GX40NiCrNb45-35 Aged be formed, bent or molded?
Shaped by casting only, as centrifugally cast tube or sand and investment castings; cold bending and cold forming are not possible. Hot straightening must be done above 1050 °C followed by slow cooling.
What is the maximum service temperature of GX40NiCrNb45-35 Aged?
GX40NiCrNb45-35 Aged is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10295 — Heat resistant steel castings — CEN (2002)
- DIN 17465 / Werkstoff-Nr. 1.4889 (historical) — DIN (1988)
- ASM Handbook Vol.1 — Heat-Resistant Castings (HK/HP/45-35 class) — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.