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Certifications: EN 10204 3.1 / 3.2 material test certificates, PMI verification, and complete export documentation packages.
Inconel
600
(UNS N06600)
A world-class technical reference for EPC contractors, process and industrial furnace engineers, procurement heads, and TPI inspection agencies specifying Inconel 600 nickel-chromium-iron alloy — the original Inconel alloy, covering its high-temperature oxidation and carburization resistance, chloride and caustic SCC performance, the well-documented primary water stress corrosion cracking (PWSCC) history in nuclear steam generator service, and the QC and documentation discipline required for critical high-temperature industrial equipment supply.
Key Properties
& Selection Logic
Inconel 600 (UNS N06600) is a nickel-chromium-iron alloy and the original member of the Inconel alloy family, first developed in the 1930s-40s — offering excellent resistance to high-temperature oxidation and carburization, strong resistance to chloride-ion and caustic stress corrosion cracking, and useful mechanical properties across an unusually broad temperature range from cryogenic to over 1000°C.
1.1 — What Inconel 600 (UNS N06600) Is
Inconel 600 is a nickel-chromium-iron alloy with a nominal composition of approximately 72% nickel (minimum), 14–17% chromium, and 6–10% iron, with the balance comprising minor elements — the original Inconel alloy, historically significant as one of the first commercially successful high-nickel-content alloys engineered specifically for combined high-temperature and aqueous corrosion resistance beyond what stainless steel could provide. Its very high nickel content (substantially higher than the Incoloy family discussed in RR Hydraulic’s Incoloy 800/825 references, and higher than most other common Inconel alloys except specialty grades) gives it distinctive resistance to specific corrosion mechanisms — chloride-ion stress corrosion cracking and caustic (alkaline) stress corrosion cracking in particular — that austenitic stainless steel is notably vulnerable to, alongside strong high-temperature oxidation and carburization resistance.
1.2 — Key Engineering Properties
Excellent High-Temperature Oxidation Resistance
Inconel 600’s chromium content forms a protective oxide surface layer providing good oxidation resistance in air and combustion atmospheres up to approximately 1150°C for intermittent exposure — supporting furnace muffle, radiant tube, heat treating fixture, and other high-temperature industrial equipment applications.
Good Carburization and Nitriding Resistance
Good resistance to carbon and nitrogen pickup from carbon-active and nitrogen-active high-temperature process atmospheres — relevant for heat treating furnace equipment (retorts, muffles, fixtures) exposed to carburizing or nitriding furnace atmospheres in metal heat treatment operations.
Excellent Chloride and Caustic Stress Corrosion Cracking Resistance
Inconel 600’s high nickel content provides substantially better resistance to chloride-ion stress corrosion cracking than standard austenitic stainless steel, and excellent resistance to caustic (alkaline) stress corrosion cracking — historically the specific property that drove the alloy’s original selection for nuclear steam generator tubing (discussed in detail in Section 1.3), where the SCC vulnerability of stainless steel in the reactor water chemistry environment was an unacceptable risk.
Good Mechanical Properties Across a Broad Temperature Range
Useful mechanical strength and toughness from cryogenic temperatures through elevated service temperature, supporting a wide range of structural, fastener, and pressure-containing applications beyond the alloy’s primary high-temperature corrosion-resistance role.
1.3 — Historical Note: Primary Water Stress Corrosion Cracking (PWSCC) in Nuclear Service
1.4 — Comparison to Related Alloys
| Alloy | Nickel Content | Chromium Content | Key Distinguishing Feature |
|---|---|---|---|
| Inconel 600 (N06600) | ~72% | 14–17% | Original Inconel alloy — high-temp oxidation resistance + Cl⁻/caustic SCC resistance |
| Alloy 690 (N06690) | ~58–63% | 27–31% | Higher chromium — superior PWSCC resistance, now standard for new nuclear steam generator tubing |
| Inconel 601 (N06601) | ~58–63% | 21–25% | Added aluminium — improved high-temperature oxidation resistance beyond Inconel 600, particularly in cyclic thermal service |
| Inconel 625 (N06625) | ~58% | 20–23% | Added Mo/Nb — combined high-temp + aqueous/sour corrosion resistance, excellent weldability (RR Hydraulic’s dedicated reference) |
| Incoloy 800 (N08800) | ~32% | 19–23% | Lower nickel, higher iron — more economical high-temperature alloy for less severe service (RR Hydraulic’s dedicated reference) |
Product Forms
& Composition Reference
Inconel 600 is manufactured across tube, pipe, bar, and plate product forms, each governed by a specific ASTM/ASME standard. Full detail on related nickel alloys is available across our standards reference library.
Submit form, size, and quantity to sales@rrhydraulics.com for a certified offer.
2.1 — Governing Standards
ASTM B166 / ASME SB-166 — Rod, Bar, and Wire
Governs Inconel 600 rod, bar, and wire stock for machined components, forging billet, and fastener manufacture.
ASTM B167 / ASME SB-167 — Seamless Pipe and Tube
Governs seamless Inconel 600 pipe and tube for process piping, furnace equipment, and heat exchanger applications.
ASTM B168 / ASME SB-168 — Plate, Sheet, and Strip
Governs flat-rolled Inconel 600 product — plate for furnace and vessel fabrication, sheet and strip for general fabrication requiring the alloy’s high-temperature or corrosion performance.
ASTM B516 / B517 — Welded Pipe and Tube
Governs welded (rather than seamless) Inconel 600 pipe and tube construction, an alternative manufacturing route for larger-diameter or specific application requirements.
ASME Section II Part B / Section VIII
Publishes design allowable stress values for Inconel 600 by temperature, referenced for pressure equipment design incorporating the alloy across its useful elevated-temperature service range.
2.2 — Chemical Composition and Mechanical Properties
| Element / Property | Value / Range |
|---|---|
| Nickel | 72.0% (min.) |
| Chromium | 14.0–17.0% |
| Iron | 6.0–10.0% |
| Carbon (max.) | 0.15% |
| Manganese (max.) | 1.0% |
| Tensile Strength | 550–690 MPa (typical, min. 550 MPa per spec) |
| Yield Strength | 240–310 MPa (typical, min. 240 MPa per spec) |
| Elongation | 35–50% |
Corrosion Performance
& Fabrication Guidance
Correct heat treatment and fabrication practice preserve Inconel 600’s designed high-temperature and corrosion performance across its broad range of industrial furnace and chemical process applications.
3.1 — Solution Annealing Heat Treatment
Inconel 600 is typically supplied in the solution-annealed condition — heated to approximately 980–1040°C and air- or water-cooled to dissolve secondary phases into solid solution and establish the optimal single-phase austenitic microstructure for both mechanical properties and corrosion resistance. Components intended for high-stress service or applications with a documented stress corrosion cracking risk (including, historically, nuclear steam generator tubing per the discussion in Section 1.3) may receive a supplementary stress-relief heat treatment or specific thermal treatment protocol to reduce residual stress from forming or machining operations — verify the specific project or application’s heat treatment requirement beyond standard mill annealing where SCC risk mitigation is a design consideration.
3.2 — Corrosion Performance by Environment
| Environment | Performance | Notes |
|---|---|---|
| High-temperature oxidizing atmosphere | Excellent to ~1150°C intermittent | Standard furnace and heat treating equipment application |
| Carburizing/nitriding atmosphere | Good | Heat treating furnace fixtures and retorts |
| Chloride stress corrosion cracking | Excellent — substantially better than austenitic stainless steel | The alloy’s signature corrosion advantage over stainless steel |
| Caustic (alkaline) stress corrosion cracking | Excellent | Used in caustic process equipment for this reason |
| Primary reactor coolant water (nuclear PWR) | Historically vulnerable to PWSCC — see Section 1.3 | Superseded by Alloy 690 for new nuclear steam generator tubing |
| General aqueous/mild acid environments | Good general corrosion resistance | Not the alloy of choice for the most aggressive acid environments — consider Incoloy 825/Hastelloy family for those applications |
3.3 — Fabrication and Welding Guidance
Weldability
Inconel 600 is readily weldable using standard nickel alloy welding processes (GTAW, GMAW, SMAW) with matching filler metal (ERNiCr-3 / ENiCrFe-2 type, per AWS A5.14/A5.11) — good weld ductility and toughness are achieved with correct procedure control and standard nickel alloy welding cleanliness discipline.
Machining Characteristics
Inconel 600 work-hardens during machining, similar to other nickel alloys discussed throughout RR Hydraulic’s materials references — appropriate tooling, cutting parameters, and coolant application are required to manage tool wear and heat generation, though the alloy is generally more machinable than age-hardened superalloys like Inconel 718.
Forming and Fabrication
Good ductility in the annealed condition supports cold forming operations (bending, drawing) for furnace component and fixture fabrication, with standard nickel alloy forming practice (appropriate die radii, adequate lubrication) applying as it does across the broader nickel alloy family.
Industry Applications
& Documentation
RR Hydraulic maintains full traceability from certified nickel alloy heat to finished, tested, and packed Inconel 600 component shipment. Chemical composition, mechanical, and PMI verification are standard on all project-grade supply.
4.1 — Inspection & QC Protocol
4.2 — EN 10204 / Documentation Requirements
| Certificate | Content | EPC Requirement | When Mandatory |
|---|---|---|---|
| 2.1 / 2.2 | Declaration / non-specific | Not acceptable for critical process/furnace supply | Never for critical high-temperature equipment supply |
| 3.1 (EN 10204) | Heat-traceable chemical + mechanical test report | Mandatory — all EPC supply | All furnace, chemical process, and general industrial component supply |
| 3.2 (EN 10204) | 3.1 + TPI countersign | Critical / owner-specified critical items | High-consequence process equipment; note that new nuclear primary coolant applications should specify Alloy 690, not 600 |
4.3 — Applications by Industry
Industrial Furnace and Heat Treating Equipment
Inconel 600 muffles, retorts, radiant tubes, and fixtures for industrial heat treating furnaces exposed to high-temperature oxidizing, carburizing, or nitriding atmospheres — one of the alloy’s largest-volume application categories, leveraging its combined oxidation and carburization resistance across a broad temperature range.
Caustic and Chloride-Bearing Chemical Process Equipment
Inconel 600 components for caustic evaporator equipment and other chemical process applications where chloride or caustic stress corrosion cracking of stainless steel is a documented concern — leveraging the alloy’s specific SCC resistance advantage discussed in Section 1.2.
Thermocouple Sheathing and High-Temperature Instrumentation
Inconel 600 protection tubes and sheaths for thermocouples and other high-temperature instrumentation in furnace and process equipment, where the alloy’s combined oxidation resistance and adequate mechanical properties provide reliable, long-service-life instrumentation protection.
4.4 — Export Packaging Specification
- Tube, pipe, and bar ends protected to prevent contamination and mechanical damage during transit, particularly important given the alloy’s typical use in high-integrity furnace and process equipment
- Heat/lot number stamped or tagged on each item, cross-referenced to the accompanying material test certificate with clear alloy grade marking (600 vs. 690 vs. 601) to prevent confusion at site receiving inspection
- Components segregated from carbon steel and other dissimilar materials during packing to avoid surface contamination affecting the alloy’s corrosion performance
- Documentation in a waterproof pocket: EN 10204 3.1/3.2 MTC, chemical composition report, mechanical properties report, PMI report, NDT reports, and packing list with form/size breakdown per item
- ISPM-15 timber or export cartons for international shipment, with country of origin and HS tariff code documentation matched to the nickel alloy product category
Submit your form, size, and quantity to RR Hydraulic for a complete, certified commercial offer.