Nickel Alloy G-NiCr50Nb-SR (Stress relieved)
Heat-treated state
EN 2.4680
Choose when thick or complex castings must be machined or welded, to reduce residual stress and cracking risk.
Values for the SR condition
Other G-NiCr50Nb tempers and conditions
G-NiCr50Nb is listed in 3 conditions; see the grade overview at G-NiCr50Nb.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SRThis page Stress relieved | Choose when thick or complex castings must be machined or welded, to reduce residual stress and cracking risk. | 370 | 560 | 6 | 20 HRC | 1.7 % IACS |
As-welded deposit | Weld-metal condition for cladding boiler supports or repairing castings with matching 50Cr-50Ni-Nb consumables. | 390 | 550 | 4 | 24 HRC | 1.7 % IACS |
FDefault As fabricated | Standard supply condition: static sand or investment castings used directly for tube supports and furnace hardware. | 400 | 580 | 5 | 22 HRC | 1.7 % IACS |
What is G-NiCr50Nb-SR?
G-NiCr50Nb-SR is G-NiCr50Nb heat treated to SR — choose when thick or complex castings must be machined or welded, to reduce residual stress and cracking risk. G-NiCr50Nb-SR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 55% of nickel alloy grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi). G-NiCr50Nb-SR 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). F is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 88% of nickel alloy grades
- Low embodied carbon — 10.5 kg CO₂/kg, better than 88% of nickel alloy grades
- High electrical conductivity — 1.7 % IACS, better than 76% of nickel alloy grades
Limitations
- Hard to polish — 55/100, worse than 95% of nickel alloy grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 93% of nickel alloy grades
- Limited ductility — 6%, worse than 90% of nickel alloy grades
- Limited formability — 6/100, worse than 88% of nickel alloy grades
- Difficult to weld — 30/100, worse than 78% of nickel alloy grades
G-NiCr50Nb-SR properties
Typical room-temperature values for G-NiCr50Nb-SR; 23 are specific to this condition. Other listed values are G-NiCr50Nb reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
G-NiCr50Nb-SR 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).
Mechanical17
G-NiCr50Nb-SR has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 55% of nickel alloy grades. Elongation at break is 6% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
G-NiCr50Nb-SR is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), better than 73% of nickel alloy grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
G-NiCr50Nb-SR conducts electricity at 1.7 % IACS, better than 76% of nickel alloy grades.
Chemical & Environmental2
Corrosion resistance is excellent (86/100), better than 77% of nickel alloy grades.
Sustainability3
Producing a kilogram of G-NiCr50Nb-SR takes about 145 MJ of energy and emits 10.5 kg of CO₂ — less than 77% of nickel alloy grades. Typical recycled content is 40%.
Manufacturability8
G-NiCr50Nb-SR's machinability is poor (15/100, worse than 76% of nickel alloy grades); weldability poor (30/100); formability not recommended (6/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G-NiCr50Nb-SR
Is G-NiCr50Nb easy to machine?
Very difficult — rigid setups, negative-rake carbide or ceramic inserts at low speed with heavy feed, or grind/EDM the hard α-Cr phase; expect short tool life.
Can G-NiCr50Nb be welded?
Weld only with matching 50Cr-50Ni-Nb filler, low heat input, preheat/interpass control and post-weld stress relief; highly sensitive to hot and reheat cracking.
Can G-NiCr50Nb be formed, bent or molded?
Not cold formable — produce by sand, investment or centrifugal casting to near-net shape with generous risering to avoid shrinkage porosity.
What surface finishes work on G-NiCr50Nb?
Grit blast and grind or belt-polish; the chromia film is self-protecting so no coating is normally applied, and the alloy cannot be anodised.
G-NiCr50Nb 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 |
|---|---|---|
| Crduplex α-Cr + Ni matrix | 48 – 52 | 50 |
| Nbcarbide former / strengthener | 1.2 – 1.8 | 1.5 |
| C | ≤ 0.1 | 0.06 |
| Si | ≤ 0.5 | 0.3 |
| Mn | ≤ 0.5 | 0.2 |
| Fe | ≤ 1 | 0.5 |
| Ti | ≤ 0.5 | — |
| Al | ≤ 0.3 | — |
| S | ≤ 0.02 | — |
| P | ≤ 0.02 | — |
| Nibalance, nominally ~47–48 % | balance | — |
G-NiCr50Nb-SR — frequently asked
What is G-NiCr50Nb-SR used for?
G-NiCr50Nb-SR is typically used for gas turbine casing components, furnace fittings and high-temperature valve bodies. In short: 50Cr-50Ni oxidation resistance; hardest cast Ni-Cr grade; grind-and-EDM material.
What is the yield strength of G-NiCr50Nb-SR?
G-NiCr50Nb-SR has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 560 MPa (81.2 ksi) — weaker than 55% of nickel alloy grades. Strength varies by condition: see the 3 listed tempers.
Is G-NiCr50Nb-SR easy to machine?
Not especially — machinability is rated poor (15/100, worse than 76% of nickel alloy grades). Very difficult — rigid setups, negative-rake carbide or ceramic inserts at low speed with heavy feed, or grind/EDM the hard α-Cr phase; expect short tool life.
Can G-NiCr50Nb-SR be welded?
Not readily — weldability is rated poor (30/100). Weld only with matching 50Cr-50Ni-Nb filler, low heat input, preheat/interpass control and post-weld stress relief; highly sensitive to hot and reheat cracking.
What surface finishes work on G-NiCr50Nb-SR?
Grit blast and grind or belt-polish; the chromia film is self-protecting so no coating is normally applied, and the alloy cannot be anodised.
Can G-NiCr50Nb-SR be formed, bent or molded?
Not cold formable — produce by sand, investment or centrifugal casting to near-net shape with generous risering to avoid shrinkage porosity.
What is the maximum service temperature of G-NiCr50Nb-SR?
G-NiCr50Nb-SR 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.
What is the difference between G-NiCr50Nb-F and G-NiCr50Nb-SR?
F is the default condition — standard supply condition: static sand or investment castings used directly for tube supports and furnace hardware. SR: choose when thick or complex castings must be machined or welded, to reduce residual stress and cracking risk. Yield strength is 400 MPa in F versus 370 MPa in SR.
Sources
- DIN 17465 — Heat resistant steel castings (G-NiCr50Nb, 2.4680) — DIN (1988)
- EN 10295 — Heat resistant steel castings — CEN (2002)
- INCONEL alloy 657 (50Cr-50Ni-Nb) technical bulletin — Special Metals Corporation (2004)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — 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.