Nickel Alloy K403
K403 is a precipitation-strengthened cast nickel-base superalloy with high Al+Ti for gamma-prime hardening, produced by vacuum induction melting followed by vacuum investment casting.
Reference datasheet — K403 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the F condition
K403 tempers and conditions
K403 is supplied in 4 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
FDefault As fabricated | Pick as the default delivery state for vacuum investment cast turbine blades and nozzle guide vanes used straight from the mould, accepting 5 % elongation and very poor machinability (score 12). | 830 | 940 | 5 | 38 HRC | 1.3 % IACS |
Solution treated 1210 °C / 4 h, air cool | Use when dendritic segregation must be homogenised and γ′ size adjusted by solution treatment at 1210 °C / 4 h and air cool, lifting elongation to 6 % and giving more consistent creep and ductility. | 840 | 960 | 6 | 39 HRC | 1.3 % IACS |
Hot isostatic pressed | Choose for high-reliability rotating blades: hot isostatic pressing at ~1200 °C / 120–150 MPa / 4 h closes casting microporosity, raising elongation to 7.5 % and both fatigue and creep life. | 850 | 985 | 7.5 | 39 HRC | 1.3 % IACS |
Hot isostatic pressed, solution treated and aged | Specify for critical long-life hot-section parts; densification followed by solution treatment and ageing refines γ′ morphology for the best overall balance of 1000 MPa tensile and 8 % elongation. | 865 | 1,000 | 8 | 40 HRC | 1.3 % IACS |
Supply forms, finishes and certifications
Ways K403 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
MASTER | Master alloy ingot | Supply option |
What is K403?
K403 is a precipitation-strengthened cast nickel-base superalloy with high Al+Ti for gamma-prime hardening, produced by vacuum induction melting followed by vacuum investment casting. Typical properties are 830 MPa yield, 940 MPa tensile, 5% elongation and 38 HRC with service to 950 °C, which suits equiaxed turbine blades and guide vanes. Ductility and fusion weldability are low and machinability is rated 12, so airfoils are cast near net shape and finished by grinding and EDM. Where higher creep life along the blade axis is needed, a directionally solidified grade such as DZ22 is used. K403 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 1,290°C (2,354 °F). K403 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 940 MPa (136 ksi) — stronger than 88% of nickel alloy grades. Elongation at break is 5% and the elastic modulus is 200 GPa (29 Msi).
What is K403 used for?
- turbine blades
- guide vanes
- industrial gas turbine hot parts
Advantages
- High strength — 830 MPa (120 ksi), better than 88% of nickel alloy grades
Limitations
- Limited formability — 3/100, worse than 97% of nickel alloy grades
- Difficult to weld — 10/100, worse than 94% of nickel alloy grades
- Limited ductility — 5%, worse than 93% of nickel alloy grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 91% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
K403 properties
Typical room-temperature values for K403-F; bars are the position among nickel alloy grades.
Physical3
K403 has a density of 8.2 g/cm³ (0.296 lb/in³), lighter than 63% of nickel alloy grades. It melts at 1,290°C (2,354 °F).
Mechanical16
K403 has a yield strength of 830 MPa (120 ksi) and a tensile strength of 940 MPa (136 ksi) — stronger than 88% of nickel alloy grades. Elongation at break is 5% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
K403 is rated for continuous service to 950°C (1,742 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 60% of nickel alloy grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
K403 conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 77% of nickel alloy grades.
Sustainability4
Producing a kilogram of K403 takes about 230 MJ of energy and emits 14.5 kg of CO₂ — more than 91% of nickel alloy grades. Typical recycled content is 25%.
Manufacturability8
K403's machinability is not recommended (12/100, worse than 86% of nickel alloy grades); weldability not recommended (10/100); formability not recommended (3/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. K403 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with K403
Is K403 easy to machine?
Extremely difficult to cut: airfoil surfaces are produced near net shape by precision casting, and fir-tree roots by creep-feed grinding, EDM or ECM. For turning and milling use solid carbide or ceramic tooling at low speed with heavy feed and ample high-pressure coolant.
Can K403 be welded?
Poor fusion weldability, as Al+Ti above 8% promotes strain-age cracking. Repair is limited to preheated vacuum brazing or laser/micro-plasma cladding followed immediately by heat treatment, and must be qualified under the applicable airworthiness repair procedure.
Can K403 be formed, bent or molded?
Vacuum induction melted master alloy is vacuum investment cast in ceramic shells with controlled pouring and cooling rates to suppress shrinkage porosity; HIP is applied for densification when required. The alloy cannot be forged or cold formed.
K403 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 |
|---|---|---|
| C | 0.11 – 0.18 | 0.15 |
| Cr | 10 – 12 | 11 |
| Co | 4.5 – 6 | 5.2 |
| W | 4.8 – 5.5 | 5.1 |
| Mo | 3.8 – 4.5 | 4.1 |
| Algamma-prime forming element | 5.3 – 5.9 | 5.6 |
| Tigamma-prime forming element | 2.3 – 2.9 | 2.6 |
| Bgrain boundary strengthening | 0.01 – 0.02 | 0.02 |
| Zr | ≤ 0.06 | 0.03 |
| Cetrace rare earth, melt purification | ≤ 0.02 | |
| Feimpurity | ≤ 2 | |
| Mnimpurity | ≤ 0.4 | |
| Siimpurity | ≤ 0.4 | |
| Pimpurity | ≤ 0.02 | |
| Simpurity | ≤ 0.01 | |
| Ni | balance |
What surface finishes work on K403?
The normal route is HIP, grit blasting or chemical cleaning, then fluorescent penetrant and X-ray inspection, followed by aluminide or MCrAlY coating. Film-cooling holes are produced by EDM or laser drilling.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
How much does K403 cost?
K403 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
K403 — frequently asked
What is K403 used for?
K403 is typically used for turbine blades, guide vanes and industrial gas turbine hot parts. In short: equiaxed 950 °C blade alloy; cast near-net airfoils; very low machinability.
What is the yield strength of K403?
K403 has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 940 MPa (136 ksi) — stronger than 88% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is K403 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 86% of nickel alloy grades). Extremely difficult to cut: airfoil surfaces are produced near net shape by precision casting, and fir-tree roots by creep-feed grinding, EDM or ECM. For turning and milling use solid carbide or ceramic tooling at low speed with heavy feed and ample high-pressure coolant.
Can K403 be welded?
Not readily — weldability is rated not recommended (10/100). Poor fusion weldability, as Al+Ti above 8% promotes strain-age cracking. Repair is limited to preheated vacuum brazing or laser/micro-plasma cladding followed immediately by heat treatment, and must be qualified under the applicable airworthiness repair procedure.
What surface finishes work on K403?
The normal route is HIP, grit blasting or chemical cleaning, then fluorescent penetrant and X-ray inspection, followed by aluminide or MCrAlY coating. Film-cooling holes are produced by EDM or laser drilling.
Can K403 be formed, bent or molded?
Vacuum induction melted master alloy is vacuum investment cast in ceramic shells with controlled pouring and cooling rates to suppress shrinkage porosity; HIP is applied for densification when required. The alloy cannot be forged or cold formed.
What is the maximum service temperature of K403?
K403 is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between K403-F and K403-HIP?
F is the default condition — pick as the default delivery state for vacuum investment cast turbine blades and nozzle guide vanes used straight from the mould, accepting 5 % elongation and very poor machinability (score 12). HIP: choose for high-reliability rotating blades: hot isostatic pressing at ~1200 °C / 120–150 MPa / 4 h closes casting microporosity, raising elongation to 7.5 % and both fatigue and creep life. Yield strength is 830 MPa in F versus 850 MPa in HIP.
How much does K403 cost?
K403 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (cast Ni superalloys) — ASM International (1990)
- Superalloys II (C.T. Sims et al.) — Wiley (1987)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.