Inconel 600 Alloy (UNS N06600)
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Inconel 600 (AMS 5540, ASTM B564)
Inconel 600 is a high-strength nickel-chromium alloy made for extreme conditions. It resists heat, corrosion, and pressure with ease. This alloy stays strong and stable from very low to very high temperatures. It works well up to 2000°F (1093°C). Inconel 600 fights oxidation, carburization, and chloride stress cracking. Because of this, it is trusted in chemical plants, aerospace parts, nuclear systems, and heat-treating tools.
This alloy offers great strength and long service life. The high nickel gives strong resistance to reducing chemicals. The chromium adds protection from oxidation and scaling. Together, they make the alloy tough and durable. Inconel 600 lasts longer and needs less maintenance than regular stainless steel. It is the best choice for furnaces, heat exchangers, and gas turbines. When the job demands strength and safety, Inconel 600 delivers every time.
Key properties
- Excellent corrosion resistance. The alloy resists many acids, alkalis, and salt solutions. It withstands chloride-induced stress corrosion in many environments. You get longer life in aggressive chemical settings.
- High temperature strength. The alloy keeps strength when heated. It resists deformation under sustained loads at elevated temperatures. You can use it in heat exchangers and furnace parts.
- Superior oxidation resistance. A stable oxide film forms on the surface. This film slows further scaling and metal loss. It suits combustion systems and high-temperature processing.
- Good creep and fatigue performance. The alloy endures long-term loads without rapid creep. It also withstands repeated thermal or mechanical cycling. That lowers replacement and downtime costs.
- Stable microstructure. The alloy resists phase changes during service. It keeps consistent mechanical properties over time. This stability aids predictable fabrication and performance.
- Good ductility and toughness. You can form and shape it by hot or cold work. Parts retain toughness at room and elevated temperatures. This property helps in complex component manufacturing.
- Weldability and fabrication-friendly. You can weld it using common methods like TIG and MIG. It accepts standard filler metals and procedures. Proper preheat and post-weld care improve results.
- Moderate thermal and electrical conductivity. It conducts heat and electricity adequately for many parts. Its conductivity stays reliable at higher temperatures. Designers can use it for heating elements and electrical fittings.
- Resistance to organic and inorganic compounds. It resists acids such as acetic and formic acids. It also tolerates many halide and neutral salt solutions. This widens its use in chemical plant service.
- Corrosion fatigue resistance. It resists crack initiation in corrosive, cyclic environments. That reduces failure risk for rotating and vibrating parts. It suits pumps, valves, and marine hardware.
- Low magnetic response. The alloy remains essentially non-magnetic in service. This helps in applications where magnetism is a concern. It aids instrumentation and certain nuclear components.
- Long service life with low maintenance. Its combined properties reduce frequent repairs. Operators see longer intervals between servicing. This lowers lifecycle cost and improves uptime.
Performance Profile:
- Corrosion Resistance: Inconel 600 resists a wide range of corrosive environments. It prevents oxidation, carburization, and chloride-ion stress corrosion cracking. The alloy stays stable in acidic and alkaline media. It performs well in steam and high-temperature gases, ensuring reliability in harsh industrial conditions.
- High Temperature Strength: Inconel 600 retains strength and ductility at high temperatures. It resists scaling and oxidation up to 1200°C (2200°F). The alloy remains stable under continuous heat and thermal cycling. It performs well in furnaces, heat exchangers, and other hot equipment.
- Oxidation and Scaling Resistance: The nickel-chromium blend forms a strong oxide layer that prevents scaling. This protection increases component life and keeps performance stable in oxidizing and reducing environments.
- Mechanical Properties: Inconel 600 shows high tensile strength and excellent toughness. It keeps mechanical stability under stress, vibration, and load changes. This makes it ideal for pressurized and rotating parts.
- Thermal Stability: The alloy expands very little under heat. It resists thermal fatigue and stays stable during fast temperature shifts. This makes it perfect for heating and cooling cycles.
- Fabrication and Weldability: Inconel 600 is easy to shape and machine. It can be welded using gas tungsten arc, gas metal arc, or resistance methods. It avoids post-weld cracking and keeps its strength after joining.
- Electrical and Magnetic Properties: The alloy has good electrical conductivity and low magnetic response. It stays non-magnetic even after long heat exposure. This makes it suitable for electrical and electronic parts.
- Long-Term Reliability: Inconel 600 delivers consistent performance where other metals fail. It resists corrosion, deformation, and scaling. It offers long service life and low maintenance costs. Its reliability ensures safe and efficient operation in every industry.
Common Applications:
Inconel 600 serves many industries. It keeps parts strong in heat and corrosion. Below is a detailed, end-to-end list of common applications. Each item shows typical parts, why Inconel 600 fits, and practical benefits.
1. Chemical Processing Equipment
- Plants use it for heat exchangers and reactor internals.
- It resists acids, alkalis, and mixed chemicals.
- Fabricators form it into piping, flanges, and pumps.
- It lowers downtime from corrosion failures.
2. Aerospace Components
- Engineers use it for turbine seals and exhaust ducts.
- It withstands very high temperatures and thermal shock.
- It keeps mechanical strength during flight cycles.
- It helps parts meet strict safety margins.
3. Power Generation Systems
- Utilities use it in steam generator tubing and boiler parts.
- It resists oxidation and carburization at high heat.
- It sustains long service life under pressure.
- It reduces the need for frequent part replacement.
4. Heat-Treating Furnaces & Fixtures
- Shops use it for trays, fixtures, and retorts.
- It holds shape through repeated thermal cycles.
- It resists scale and surface attack at furnace temperatures.
- It improves yield and lowers scrap rates.
5. Nuclear Industry
- Engineers use it for certain reactor components and supports.
- It offers dimensional stability and corrosion resistance.
- It performs under radiation and high-temperature steam.
- It helps maintain long-term structural integrity.
6. Marine and Offshore Equipment
- Shipbuilders fit it in seawater-exposed valves and shafts.
- It resists pitting and crevice corrosion from salt water.
- It works well on rigs and subsea hardware.
- It extends service life in harsh sea environments.
6. Oil & Gas Processing
- Refineries use it in heaters, piping, and fittings.
- It resists sour gas and fouling in high heat.
- It tolerates repeated startup and shutdown cycles.
- It improves safety and reduces leak risks.
8. Food Processing & Pulp & Paper
- Plants use it where organic acids and caustics appear.
- It prevents contamination of food products.
- It cleans easily and withstands sanitary procedures.
- It prolongs equipment life under chemical attack.
9. Electronics & Instrumentation
- Manufacturers use it for thermocouple sheaths and resistive elements.
- It stabilizes electrical sensors at high temperatures.
- It resists oxidation that can change readings.
- It ensures reliable instrument performance over time.
10. Automotive & Exhaust Systems (High-Performance)
- Makers use it for turbocharger and exhaust sections
- It handles cyclic thermal loads well.
- It prevents scale and oxidation at exhaust temperatures.
- It helps performance vehicles run reliably under stress.
11. Furnace Components & Retorts
- Foundries and labs use it for retorts and shields.
- It resists carburizing and hostile furnace atmospheres.
- It keeps tight tolerances after many cycles.
- It lowers maintenance and replacement costs.
12. Industrial Valves, Fasteners & Hardware
- Facilities use it for bolts, nuts, and critical valve parts.
- It keeps threads and seals stable at high heat.
- It resists galling and seizing in service.
- It ensures safer, longer-lasting assemblies.
13. Heat Exchangers & Condensers
- Chemical and power plants use it for tube bundles.
- It resists corrosion from mixed media and steam.
- It holds thermal conductivity and strength over time.
- It reduces leaks and performance loss.
14. Manufacturing Tools in Aggressive Environments
- Shops use it for dies and tooling where chemicals attack steel.
- It keeps geometry under corrosive exposure.
- It lowers tool change frequency.
- It improves process consistency.
15. Custom & Specialty Applications
- Engineers choose it for bespoke parts that face extreme stress.
- It works well in hybrid alloys and cladding.
- Fabricators weld and machine it into complex shapes.
- It provides tailored solutions for niche problems.
Specifications:
- UNS N06600
- ASTM B166 / B167 / B168 / B163 / B564
- ASME SB166 / SB167 / SB168 / SB163 / SB564
- AMS 5540
- 2.4816
- NiCr15Fe / EN 10095: 2.4816
- NiCr15Fe
- NA 13
- NC15FE / NCF 600
- NCF 600 / JIS NCF60
- ЭИ868 (EI868)
- ISO 15156 / NACE MR0175
Chemical Composition (WT %):
| Element | Symbol | Weight Percentage (WT %) | Function / Significance |
|---|---|---|---|
| Nickel | Ni | 72.0 min | Provides exceptional resistance to corrosion, particularly in reducing environments. It ensures stability across high and low temperatures and enhances ductility and toughness. |
| Chromium | Cr | 14.0 – 17.0 | Strengthens oxidation resistance in high-temperature atmospheres and adds resistance to sulfur compounds and other oxidizing agents. |
| Iron | Fe | 6.0 – 10.0 | Improves structural rigidity and thermal stability, contributing to the alloy’s mechanical balance and cost efficiency. |
| Carbon | C | 0.15 max | Maintains strength and hardness while keeping the alloy resistant to grain boundary corrosion. Low carbon ensures weldability. |
| Manganese | Mn | 1.0 max | Enhances hot-working characteristics and improves toughness under mechanical stress. |
| Sulfur | S | 0.015 max | Controlled to a very low level to prevent hot cracking and maintain high purity and corrosion resistance. |
| Silicon | Si | 0.50 max | Aids in oxidation resistance and improves high-temperature stability by forming a protective oxide layer. |
| Copper | Cu | 0.50 max | Adds additional corrosion resistance, particularly in marine and acidic environments. |
| Aluminum | Al | 0.50 max | Strengthens the protective oxide film and improves the material’s surface stability at elevated temperatures. |
| Titanium | Ti | 0.50 max | Refines grain structure and enhances the alloy’s creep resistance and thermal stability. |
Physical Properties:
| Property | Typical value (range where applicable) | Units | Notes / Test Condition |
|---|---|---|---|
| Alloy designation | Inconel 600 (UNS N06600) | — | Nickel-chromium alloy |
| Density | 8.47 | g/cm³ | ≈ 8470 kg/m³ |
| Phase structure | Single-phase FCC (austenitic) | — | Stable austenitic structure at RT |
| Melting / solidus-liquidus | 1370 – 1425 | °C | Melting range (approx.) |
| Modulus of elasticity (Young’s modulus) | ≈ 205 | GPa | Room temperature |
| Poisson’s ratio | ≈ 0.29 | — | Typical for nickel alloys |
| Thermal conductivity | 11 – 14 | W·m⁻¹·K⁻¹ | Room temperature; decreases at high T |
| Specific heat capacity (Cp) | ≈ 435 | J·kg⁻¹·K⁻¹ | At ~20–100 °C (0.435 kJ·kg⁻¹·K⁻¹) |
| Coefficient of thermal expansion (CTE) | ≈ 13.3 ×10⁻⁶ | /°C | 20–100 °C typical; increases with T |
| Electrical resistivity | ≈ 100 | µΩ·cm (≈1.0×10⁻⁶ Ω·m) | At 20 °C; alloy and cold-work alter value |
| Magnetic behavior | Essentially non-magnetic | — | May show slight ferromagnetism if cold-worked |
| Hardness (annealed) | HRB ~70 – 100 | Rockwell B | Varies with product form and cold work |
| 0.2% Proof (yield) strength (annealed) | ≈ 205 | MPa | Typical room-temp value; depends on temper |
| Ultimate tensile strength (annealed) | ≈ 515 – 620 | MPa | Room temperature, annealed condition |
| Elongation (annealed) | 30 – 50 | % | Percent elongation in 50 mm gauge typical |
| Reduction of area (typ.) | 35 – 60 | % | Depends on product and test |
| Recommended continuous service temperature | Up to ≈ 700 | °C | Shorter exposures possible at higher T |
| Maximum intermittent service | ≈ 1000 | °C | Application-dependent; oxidation and strength limits |
| Thermal shock resistance | Good | Qualitative | High strength retention; depends on section size |
| Weldability & fabrication | Excellent | Qualitative | Readily welded; standard filler metals used |
| Corrosion resistance (qualitative) | Excellent to very good | Qualitative | Strong resistance to oxidizing and many reducing environments; contact supplier for specific media |
| Workability (forming) | Good (annealed) | Qualitative | Cold-work hardens the alloy; anneal to restore ductility |
| Typical surface scale / oxidation behavior | Forms protective oxide layer (Cr-rich) | Qualitative | Good high-temp oxidation resistance |
Mechanical Properties
| Property | Symbol / Unit | Typical Value (Room Temp) | Range / Notes |
|---|---|---|---|
| Density | ρ | 8.47 g/cm³ (0.306 lb/in³) | From Special Metals Table 2 (typical). |
| Melting range | — | 1354 – 1413 °C (2470 – 2575 °F) | Reported melting range (solidus–liquidus). |
| Young’s modulus (tension) | E | 214 GPa (≈214 000 MPa) at 22 °C | Falls with temperature (e.g., ~199 GPa at 300 °C). |
| Shear modulus | G | 80.8 GPa (RT) | Values decline with temperature. |
| Poisson’s ratio | ν | 0.324 (RT) | Small variation with temperature. |
| Tensile strength (ultimate, UTS) — annealed | UTS | 550 – 690 MPa (typical for annealed rod/bar) | Higher for cold-worked or hard tempers (e.g., 725–1035 MPa as-drawn/cold). |
| Yield strength (0.2% offset) — annealed | Rp0.2 / YS | 170 – 345 MPa (typical, annealed forms) | Many form/temper dependent ranges in the datasheet (rod, plate, tube). |
| Elongation (in 50 mm or specified gauge) | A% | 55 – 35 % (annealed typical) | Heavily cold-worked material shows much lower elongation. |
| Reduction of area (RA) | RA% | ~60–70% (typical examples reported) | Depends on form/temper and test specimen. |
| Hardness (Rockwell B) — annealed | HRB | 65 – 85 HRB (annealed typical for rod/plate) | Hardness increases with cold work; some tempers are given as HRB 90+ or HRC values for heavily worked conditions. |
| Hardness (Rockwell C) — hard tempers | HRC | Up to ~30–35 HRC (hard tempers) | See datasheet for specific temper conversions. |
| Fatigue strength / endurance | — | Good fatigue resistance for high-temp service (data available) | Fatigue (rotating-beam / LCF) data provided in Special Metals; values vary with temperature and condition. |
| Creep & rupture (elevated T) | — | Useful creep resistance to ~600–1150 °C depending on condition | Detailed creep-rupture tables and curves in datasheet; not precipitation-hardening (strength via cold work). |
| Thermal conductivity (RT) | k | ≈ 14.9 W/m·K (≈ at 20 °C) | Falls slightly with temperature; table available. |
| Specific heat | cp | ≈ 444 J/kg·K (≈ 0.106 Btu/lb·°F) at RT | See thermal properties table for temperature dependence. |
| Coefficient of linear thermal expansion | α (mean) | ~10.4 µm/m·°C (20 → 100 °C) | Increases with temperature; full expansion table in datasheet. |
| Electrical resistivity (RT) | ρₑ | ≈ 1.03 µΩ·m | Given in datasheet (typical). |
| Magnetic behavior | — | Paramagnetic / essentially non-magnetic at RT | Curie temp ~ −124 °C; suitable for nuclear/reactor uses. |
| Work hardening / formability | — | Readily cold-worked; can be strengthened by cold work | Fabrication guidance and typical temper tables available in datasheet. |
| Weldability & fabrication | Excellent | Qualitative | Readily welded; standard filler metals used. |
| Corrosion resistance (qualitative) | Excellent to very good | Qualitative | Strong resistance to oxidizing and many reducing environments; contact supplier for specific media. |
| Workability (forming) | Good (annealed) | Qualitative | Cold-work hardens the alloy; anneal to restore ductility. |
| Typical surface scale / oxidation behavior | Forms protective oxide layer (Cr-rich) | Qualitative | Good high-temp oxidation resistance. |
Heat treatment:
| Process / Step | Purpose | Temperature (°C) | Soak / Hold Time (guideline) | Cooling Method | Microstructure / Effect | Typical Applications / When to use | Key Notes & Precautions |
|---|---|---|---|---|---|---|---|
| Solution anneal (full anneal) | Restore ductility, dissolve carbides, homogenize alloy after fabrication or heavy cold work | 1,020 – 1,120°C | 15–60 min depending on section thickness (longer for heavy sections) | Rapid cooling (air or water quench) to avoid precipitation | Produces a homogenized, single-phase solid-solution microstructure; reduces prior cold-work hardening | After heavy cold working, before final machining or service where maximum corrosion resistance is required | Avoid slow cooling through 600–900°C range to minimize carbide precipitation and sensitization |
| Stress relieving (general) | Reduce residual stresses from forming, welding or machining without major microstructure change | 600 – 760°C | 1–4 hours (depends on mass and residual stress level) | Air cool / furnace cool | Relieves residual stress; minimal change to solid-solution structure | After forming, bending, moderate machining; when distortion or cracking risk from residual stress is a concern | Keep temperature below solution anneal; excessive temp/time can cause grain growth or sensitization in certain conditions |
| Post-weld heat treatment (PWHT) / weld stress relief | Relieve weld-induced stresses and reduce risk of stress-corrosion cracking in some assemblies | 650 – 750°C (typical weld-relief range) | 1–3 hours depending on weld size and thickness | Controlled air or furnace cooling | Reduces residual stresses near welds; can reduce susceptibility to certain cracking modes | For large weldments where distortion or stress-corrosion is a concern. PWHT is not always required for Inconel 600 — evaluate per code/spec. | Avoid temperatures and hold times that promote carbide precipitation; if design code prohibits PWHT, follow code. Monitor for oxidation/scaling if exposed in-air at these temps. |
| Recrystallization / anneal after heavy cold work | Re-crystallize and restore ductility after heavy cold deformation | ~1,000 – 1,080°C (within solution anneal range) | Long enough to fully recrystallize (dependent on thickness) | Rapid cooling recommended | New equiaxed grains, relief of strain hardening | After heavy cold working where recrystallization is required for forming or service | Use the higher end of range for thicker sections; verify grain size requirements |
| Stabilization (not typical for Inconel 600) | For some alloys stabilization (e.g., Ti or Nb additions) ties up C — Inconel 600 is not normally stabilized | N/A | N/A | N/A | N/A | Not commonly used — choose stabilized grades if required for specific environments | If carbide precipitation and sensitization are a critical risk, consider different alloy or specification |
| Aging / precipitation hardening | Produce hardening via precipitation — Inconel 600 is a solid-solution alloy and is not effectively age-hardened | N/A (not applicable) | N/A | N/A | N/A | Not applicable — choose precipitation-hardening alloys (e.g., Inconel 718) if required | Do not expect aging to increase strength in Inconel 600 |
| Surface bright anneal / decarburizing control | Reduce surface oxides or produce bright finish after cleaning | 850 – 1,050°C in controlled atmosphere | Short hold sufficient to affect surface | Controlled atmosphere cooling | Reduces surface oxidation/scaling; improves surface finish | When surface appearance or cleanliness is required (e.g., fittings, visible parts) | Use controlled atmosphere (vacuum or inert gas) to avoid heavy oxidation/scaling |
| Hydrogen or vacuum anneal (special cases) | Remove gases, prevent oxidation, produce very clean surface | Process dependent — often similar or slightly higher than solution anneal but in vacuum | Hold as required by vacuum furnace practice | Slow or controlled furnace cooling in vacuum/inert | Clean surface, minimal scale, controlled microstructure | For components needing low surface contamination or for subsequent brazing/clean-room service | Requires appropriate furnace equipment; follow supplier/AMS/ASTM guidance |
| Final stress check & inspection | Verify residual stress reduction & dimensional stability | N/A (inspection step) | N/A | N/A | N/A | After heat treatment and cooling, before final machining or assembly | Perform NDT, dimensional checks, hardness tests, or metallography as required |
Frequently Asked Questions (FAQs):
What is Inconel 600 and what makes it unique?
Inconel 600 is a nickel-chromium alloy. It resists heat, oxidation, and corrosion. High nickel content protects against chloride stress cracking. Chromium adds strength and oxidation resistance. It performs well where stainless steels fail.
What are the main applications of Inconel 600?
Industries use Inconel 600 in chemical plants, furnaces, and power systems. It is ideal for heat exchangers, aerospace parts, and reactor vessels. The alloy performs safely in high-pressure and high-temperature environments.
How does Inconel 600 perform at high temperatures?
Inconel 600 stays strong at high heat. It resists scaling and deformation. It keeps stability up to 1150°C (2100°F). This makes it ideal for heat treatment and thermal cycle operations.
What are the advantages of Inconel 600 over stainless steel?
Inconel 600 lasts longer than stainless steel in harsh settings. It resists oxidation, carburization, and chloride corrosion. It keeps strength at higher temperatures. It reduces maintenance and extends equipment life.
Is Inconel 600 available in different forms and sizes?
Yes. Inconel 600 comes in bars, sheets, plates, pipes, and tubes. It is also available in fittings. Supreme Special Steels supplies custom sizes that meet global standards and industry needs.