Alloy 600,Inconel 600 Foil，Shim,UNS N06600

Alloy 600,Inconel 600 Wire,UNS N06600

Introduction to Alloy 600 (Inconel 600 Wire, UNS N06600)

Alloy 600, commercially known as Inconel 600 and classified under UNS N06600, is a classic nickel-chromium-iron superalloy celebrated for its exceptional corrosion resistance, thermal stability, and versatility across a broad temperature range. Operating reliably from cryogenic conditions (-253°C/-423°F) up to 1095°C/2000°F, it owes its performance to a solid-solution strengthened austenitic microstructure—where chromium delivers oxidation and corrosion resistance, while nickel ensures ductility and structural stability. Unlike precipitation-hardened alloys, Alloy 600 requires no post-fabrication aging, simplifying manufacturing while maintaining consistent performance. Inconel 600 wire, a key form of this alloy, is widely used in industries such as chemical processing, nuclear power, marine engineering, and aerospace, where it excels in applications like corrosion-resistant fasteners, thermocouple sheaths, and high-temperature sensor wires. Its enduring popularity stems from a rare balance of reliability, processability, and resistance to both aggressive chemicals and extreme thermal cycling.

1. Chemical Composition (Typical, wt%)

The chemical composition of UNS N06600 adheres to strict industry standards including ASTM B625 (for nickel-alloy wire), ASTM B168 (for nickel-alloy sheet/plate), and ASME SB625, ensuring consistent corrosion resistance, mechanical strength, and thermal stability. The typical composition is as follows:

Element

Content Range (wt%)

Function

Nickel (Ni)

72.0 min.

Serves as the primary matrix element, stabilizing the austenitic structure; enhances resistance to reducing environments (e.g., hydrogen gas) and maintains ductility at cryogenic temperatures.

Chromium (Cr)

14.0 - 17.0

Forms a dense, adherent chromium oxide (Cr₂O₃) layer, providing oxidation resistance up to 1095°C and resistance to pitting/crevice corrosion in chloride-containing media (e.g., seawater, brines).

Iron (Fe)

6.0 - 10.0

Improves hot workability (critical for wire rod production) and controls alloy cost; enhances thermal conductivity without compromising corrosion performance.

Carbon (C)

≤ 0.15

Forms fine carbides (e.g., Cr₂₃C₆) at grain boundaries, improving high-temperature strength; controlled to avoid excessive carbide precipitation (which can reduce ductility in cyclic thermal environments).

Manganese (Mn)

≤ 1.0

Aids in deoxidation during melting and improves cold workability for fine wire drawing; limited to avoid brittleness at elevated temperatures.

Silicon (Si)

≤ 0.5

Promotes oxide layer adhesion and reduces molten alloy viscosity during casting; controlled to avoid excessive silica inclusions (which degrade corrosion resistance).

Copper (Cu)

≤ 0.5

Minimized to avoid interference with the chromium oxide layer and prevent hot cracking during fabrication.

Phosphorus (P)

≤ 0.03

Strictly limited to prevent grain boundary embrittlement, especially in welded joints or components exposed to acidic environments.

Sulfur (S)

≤ 0.015

Minimized to prevent hot cracking during wire drawing and welding, and to reduce corrosion susceptibility in sulfur-rich media (e.g., sour gas).

Aluminum (Al)

≤ 0.3

Trace element that refines grain structure and enhances oxide layer stability; controlled to avoid brittle intermetallic phases.

Titanium (Ti)

≤ 0.3

Trace element that supplements grain refinement and improves high-temperature creep resistance; limited to avoid carbide formation that reduces ductility.

2. Physical Properties

Inconel 600 wire exhibits stable physical properties across its extensive operating temperature range, with mechanical performance derived from solid-solution strengthening—eliminating the need for age hardening. Key properties (measured at room temperature unless specified otherwise) are:

Property

Value

Test Condition

Density

8.47 g/cm³

Room temperature (25°C)

Melting Point Range

1370 - 1425°C

-

Thermal Expansion Coefficient

13.1 × 10⁻⁶/°C

20 - 100°C; 16.5 × 10⁻⁶/°C (20 - 1000°C)

Thermal Conductivity

11.7 W/(m·K)

100°C; 22.7 W/(m·K) (1000°C)

Electrical Resistivity

1.30 × 10⁻⁶ Ω·m

Room temperature (25°C); 1.62 × 10⁻⁶ Ω·m (1000°C)

Modulus of Elasticity

207 GPa

Room temperature (tensile); 138 GPa (1000°C)

Poisson’s Ratio

0.30

Room temperature

Curie Temperature

≈ -196°C

Below this temperature, weakly ferromagnetic (irrelevant for most application temperatures).

Tensile Strength

≥ 655 MPa

Room temperature; ≥ 240 MPa (1000°C)

Yield Strength (0.2% Offset)

≥ 275 MPa

Room temperature; ≥ 130 MPa (1000°C)

Elongation

≥ 30%

Room temperature; ≥ 40% (-196°C, liquid nitrogen)

Hardness (Annealed)

≤ 220 HB

Room temperature

Creep Rupture Strength

95 MPa

1000 hours at 800°C; 35 MPa (1000 hours at 1000°C)

Oxidation Resistance

Weight gain ≤ 0.2 g/m²·h

1000°C in air (after 1000 hours, no oxide spallation)

3. Production Process of Inconel 600 Wire

The manufacturing of Inconel 600 wire focuses on preserving its solid-solution microstructure, ensuring corrosion resistance, and maintaining dimensional accuracy—with no need for age hardening, simplifying the process compared to precipitation-hardened alloys. Key steps include:

3.1 Raw Material Melting & Casting

Melting: High-purity raw materials (nickel, chromium, iron, etc.) are melted via vacuum induction melting (VIM) or air induction melting with argon degassing (AIM-AD). This process eliminates gaseous impurities (O₂ < 25 ppm, N₂ < 40 ppm) and ensures uniform distribution of chromium—critical for consistent oxide layer formation and corrosion resistance.

Casting: Molten alloy is cast into ingots (600 - 3000 kg) or blooms, which undergo homogenization annealing at 1150 - 1200°C for 8 - 10 hours. This step eliminates chemical segregation (especially of chromium) and dissolves coarse carbides, preparing the material for hot working while preserving ductility.

3.2 Hot Working & Wire Rod Production

Hot Rolling: Ingots/blooms are hot-rolled at 1050 - 1150°C into wire rods (diameter: 8 - 20 mm). Hot rolling breaks down coarse grains and improves workability; rods are air-cooled to room temperature at a controlled rate (50 - 100°C/hour) to avoid rapid carbide precipitation—ensuring uniform mechanical properties.

Descaling: Hot-rolled rods undergo shot blasting (to remove loose oxide scale) followed by acid pickling (nitric-hydrofluoric acid solution) to eliminate residual chromium oxide layers. This step prevents surface defects during cold drawing and ensures clean oxide layer formation in final applications.

3.3 Cold Drawing (Wire Formation)

Multi-Pass Cold Drawing: Wire rods are cold-drawn through diamond dies in 6 - 9 passes to achieve the desired diameter (typically 0.1 mm - 10 mm). Each pass reduces diameter by 15 - 20%, with intermediate annealing (980 - 1050°C for 30 - 60 minutes, water-quenched) between passes. This annealing step relieves work hardening, restores ductility (preventing wire breakage), and maintains the solid-solution microstructure—critical for consistent corrosion performance.

Dimensional Control: Tension, die alignment, and drawing speed are precisely regulated to maintain tight diameter tolerance (±0.015 mm for precision wire) and roundness (≤0.008 mm). For applications like thermocouple sheaths or medical devices, laser diameter monitoring ensures consistency, as dimensional variations can affect functionality (e.g., temperature measurement accuracy).

3.4 Final Heat Treatment (Stress Relief & Stability)

Inconel 600 wire undergoes stress-relief annealing to optimize its performance in service:

Stress Relief: Heating the wire to 850 - 900°C for 1 - 2 hours, followed by air cooling. This step reduces residual stresses from cold drawing, stabilizes the grain structure, and promotes uniform carbide distribution—enhancing creep resistance and reducing the risk of stress corrosion cracking (SCC) in harsh environments.

Oxide Layer Activation (Optional): For applications requiring immediate oxidation resistance (e.g., furnace heating elements), the wire is heated to 1000 - 1050°C in air for 1 hour. This forms a pre-conditioned chromium oxide layer, eliminating the need for "break-in" oxidation in service.

3.5 Surface Finishing & Quality Inspection

Surface Treatment:

Pickling: Post-annealing pickling in nitric acid to remove surface oxides and ensure clean adhesion of the protective chromium oxide layer—critical for marine or chemical applications.

Passivation: Optional nitric acid or chromate passivation to further strengthen the oxide layer, reducing the risk of pitting corrosion in chloride-rich environments (e.g., seawater, chemical reactors).

Polishing: For high-precision applications (e.g., pharmaceutical equipment, aerospace sensors), the wire is polished to a smooth surface finish (Ra ≤ 0.15 μm) using abrasive belts or electrochemical polishing, minimizing contamination risks and stress concentrations.

Quality Control:

Chemical Analysis: Optical emission spectroscopy (OES) to verify nickel and chromium content—critical for corrosion resistance and thermal stability.

Mechanical Testing: Tensile testing (strength/elongation at room and extreme temperatures), hardness testing (HB), and fatigue testing (for cyclic-loading components like springs).

Corrosion Testing: Salt spray testing (ASTM B117), crevice corrosion testing (ASTM G48), and stress corrosion cracking testing (ASTM G36) to validate resistance to harsh environments.

Non-Destructive Testing: Eddy current testing (for surface defects like cracks or pits) and ultrasonic testing (for internal flaws)—essential for nuclear or aerospace components.

Dimensional Inspection: Laser measurement to confirm diameter, straightness (≤0.08 mm/m), and length accuracy. For coil wire, payout tension testing ensures consistent unwinding during fabrication.

4. Product Applications

Inconel 600 wire’s unique combination of corrosion resistance, thermal stability, and processability makes it indispensable in industries requiring reliability across diverse environments:

4.1 Chemical & Petrochemical Industry

Corrosion-Resistant Components: Fine wire (0.2 - 1.0 mm) for manufacturing wire mesh filters, sensor probes, and fasteners in sulfuric acid (H₂SO₄), nitric acid (HNO₃), and acetic acid production—resists both oxidizing and reducing acids.

Reactor Internals: Wire for agitator springs and thermocouple sheaths in high-temperature chemical reactors (e.g., polyethylene synthesis)—withstands 800 - 1000°C and resists polymer-induced fouling.

Pump & Valve Components: Small-diameter wire for valve stems and pump shafts in chemical transport systems—maintains integrity in aggressive media (e.g., organic solvents, molten salts) without degradation.

4.2 Nuclear Power

Reactor Auxiliary Systems: Wire for control rod guides, coolant circulation tubes, and thermocouple sheaths in pressurized water reactors (PWRs) and boiling water reactors (BWRs)—low neutron absorption, resistance to borated water corrosion, and stability under radiation.

Spent Fuel Storage: Wire for structural supports in spent fuel pools—resists long-term corrosion in demineralized water and maintains strength at 40 - 60°C.

4.3 Marine Engineering

Offshore Platforms: Wire for mooring line tensioners, subsea electrical cables, and riser components—resists seawater corrosion (3.5% NaCl) and biofouling, even in deep-sea environments (up to 3000 meters depth).

Naval Vessels: Wire for hull fasteners, propeller shafts, and heat exchanger tubes—outperforms stainless steel in saltwater, extending service life and reducing maintenance costs.

Coastal Infrastructure: Wire for corrosion-resistant fencing and structural supports in coastal power plants—resists salt spray and atmospheric corrosion.

4.4 Aerospace & Defense

Aircraft Systems: Wire for engine exhaust components, fuel lines, and hydraulic system fasteners—resists 600 - 900°C exhaust gases and hydraulic fluid corrosion.

Spacecraft Components: Wire for cryogenic fuel line supports (liquid oxygen, liquid hydrogen)—maintains ductility at -196°C to -253°C and resists space radiation.

Military Equipment: Wire for armor plating fasteners and missile guidance system components—balances strength with corrosion resistance in extreme environments (e.g., desert, arctic).

4.5 Medical & Pharmaceutical Industries

Pharmaceutical Manufacturing: Sanitary wire for mixing blades and filtration systems in drug production—complies with FDA standards (21 CFR Part 177) for food/drug contact and resists cleaning agents (e.g., sodium hydroxide, hydrogen peroxide).

Medical Devices: Ultra-fine wire (0.05 - 0.2 mm) for surgical instruments, implantable devices (e.g., pacemaker leads), and dental tools—biocompatible (ISO 10993), resists bodily fluid corrosion, and maintains strength at body temperature (37°C).

Conclusion

Alloy 600 (Inconel 600 Wire, UNS N06600) is a timeless superalloy wire, distinguished by its exceptional corrosion resistance, thermal stability, and versatility. Its solid-solution strengthening and simplified manufacturing (no age hardening) make it a reliable choice for critical applications in chemical processing, nuclear power, and aerospace—where consistency and durability are non-negotiable. Whether used in acid reactors, nuclear coolant systems, or deep-sea equipment, Inconel 600 wire delivers long-term performance under extreme conditions. For custom requirements—such as ultra-precision wire (down to 0.01 mm diameter), specialized surface finishes (e.g., electropolishing), or large-diameter wire (up to 12 mm) for structural components—manufacturers offer tailored solutions to meet unique application challenges.

Packing of Standard Packing: 

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 725 gallon liquid totes Special package is available on request.