 |
Material: Inconel 600, 601, 625, 718
Type: Plate, Sheet, Strip and Coil
Thickness: 0.3-1200mm, customized
Width: 0-2500mm, customized
Length: 0-12m, customized
Surface: No.1 No.2D No.2B BA No.3 No.4 No.6 No.7, etc
Inconel sheet is supplied in thicknesses from 0.3 mm (shim stock) to over 100 mm (heavy plate), in widths up to 2 500 mm, and in cut lengths or coil form. It is routinely fabricated by standard sheet-metal processes — shearing, punching, roll forming, pressing, spinning, and welding.
Type | Plate, Sheet, Strip, Coil | |
|---|---|---|
Surface | No.1 No.2D No.2B BA No.3 No.4 No.6 No.7 | |
Size | Width: 0-2500mm / Customized | |
Manufacturing Technique | Hot / Cold Rolled | |
Packing | Steel Frame, waterproof paper, wooden palet, wooden case or as per the dient's requirements | |
Inconel Grades | Inconel 625, 600, 601, 718 | |
Inconel sheet's nickel content of 50–76 wt%, which provides three critical performance pillars:
•Oxidation resistance: The high chromium level (14–22 wt%) combined with aluminium in grades 601 and 617 forms a tenacious, self-healing Cr₂O₃ / Al₂O₃ oxide scale that resists spalling under thermal cycling up to 1 093 °C.
•Aqueous corrosion resistance: Nickel and molybdenum provide strong resistance to reducing acids (H₂SO₄, HCl) while chromium guards against oxidising media and chloride pitting.
•High-temperature mechanical strength: Solid-solution strengthening (Alloys 600, 625) and precipitation hardening via γ″ (Ni₃Nb) or γ′ (Ni₃Al,Ti) phases (Alloys 718, X-750) maintain tensile and creep-rupture properties well above the capability of austenitic stainless steels.
Inconel flat products are produced in several distinct forms. The correct selection depends on the thickness required, the surface condition needed, and the subsequent fabrication method.
Hot-rolled plate is produced by rolling ingot or slab above the alloy's recrystallisation temperature (typically 1 050–1 180 °C for Inconel grades). The resulting product has a black-oxide mill scale that must be removed by descaling or pickling before use. Hot-rolled plate is the most cost-effective form for structural or pressure-vessel applications where tight surface tolerances are not required.
•Typical thickness: 6.35 mm – 150 mm
•Width: up to 2 500 mm
•Tolerances: per ASTM A480 / EN 10029
•Condition: hot-rolled & annealed (HRA), or as-rolled
•Best for: pressure vessels, heat-exchanger tube sheets, reactor linings, structural sections
Cold-rolled sheet is produced by further reducing annealed hot-band material through cold-rolling mills at room temperature, followed by a final solution-anneal heat treatment and pickling. Cold rolling refines grain size, tightens dimensional tolerances, and improves surface quality.
•Typical thickness: 0.3 mm – 6.0 mm
•Width: up to 1 500 mm (standard); 2 000 mm (wide format)
•Tolerances: per ASTM A480 (Sheet) or EN 10259
•Condition: cold-rolled & annealed (CRA) or cold-rolled, annealed & pickled (CRAP)
•Best for: aerospace skins, turbine shrouds, chemical-plant internals, architectural cladding
Strip and coil are produced from cold-rolled sheet by slitting to narrower widths, typically ≤ 600 mm. Coil form reduces handling costs for high-volume stamping, roll-forming, and tube-mill operations.
•Typical thickness: 0.1 mm – 3.0 mm
•Width: 6 mm – 600 mm
•Supply form: inner-diameter-wound coils, precision-slit edges (milled or deburred)
•Best for: formed components, spiral-welded tube, spring elements, bellows
Surface condition is a critical variable in Inconel sheet selection. It affects corrosion performance, weldability, cleanability, and aesthetic suitability. The terminology follows ASTM A480/EN 10088 finish designations.
No. 1 — Hot-Rolled, Annealed, and Descaled (Pickled)
Produced by hot-rolling, followed by annealing and acid pickling to remove mill scale. The result is a rough, dull surface with visible rolling texture. It is the most economical finish and is used wherever surface aesthetics are irrelevant.
• Ra (roughness): typically 3–8 μm
• Applications: pressure-vessel plates, heat-exchanger tube sheets, structural linings
2D — Cold-Rolled, Annealed, and Pickled
After hot-rolling, the material is cold-reduced to gauge, annealed, and pickled. A dull, matte grey surface is produced that is suitable for most corrosive-service applications. Pickling with HNO₃/HF acid mixtures removes the annealing oxide and re-establishes the chromium-rich passive film.
• Ra: 0.5–2.5 μm
• Applications: chemical-plant piping internals, offshore fabrications, subsea components
2B — Cold-Rolled, Annealed, Pickled, and Skin-Passed
The 2B finish adds a light skin-pass rolling (< 1 % reduction) through polished rolls after pickling. This imparts a smooth, semi-reflective, slightly brighter appearance than 2D. It is the most widely specified finish for Inconel sheet used in chemical processing.
• Ra: 0.1–0.5 μm
• Applications: the standard finish for chemical plant, food-grade equipment, laboratory furniture
BA — Bright Annealed
Bright annealing is carried out in a controlled hydrogen-nitrogen atmosphere furnace, avoiding formation of surface oxides entirely. The result is a highly reflective, almost mirror-like surface requiring no subsequent pickling. BA finish preserves the maximum corrosion resistance because the passive film is never disrupted by scale formation.
• Ra: 0.05–0.2 μm
• Applications: pharmaceutical reactors, ultra-pure semiconductor gas-distribution systems, food-processing vessels
No. 3 (Brushed, 120-Grit)
A unidirectional brushed finish produced with 120-grit abrasive belts. Used in architectural cladding, kitchen equipment, and signage.
No. 4 (Brushed, 180-Grit)
Fine directional grinding lines; the most common polished finish for general stainless-steel and nickel-alloy equipment. Easier to clean than No. 3.
• Ra: 0.2–0.5 μm
• Applications: food-contact surfaces, pharmaceutical enclosures, visible architectural elements
No. 6 (Satin, Tampico Brush)
A dull satin finish produced by Tampico brushing over a No. 4 finish. Softer visual appearance, sometimes specified for decorative panels.
No. 7 (Reflective, Buffed)
High-luster buffed finish with fine directional lines barely visible. Produced by successive fine-grit abrasive steps.
No. 8 (Mirror Polish)
The highest reflectivity, produced by fine polishing compounds until all grit lines are removed. Specified for semiconductor, optical, and premium architectural applications.
• Ra: ≤ 0.05 μm
• Applications: semiconductor fab, optical components, premium architectural cladding
Inconel sheet is produced in four commercially dominant grades.
Grade | UNS No. | Ni | Cr | Fe | Mo | Nb+Ta | Al+Ti |
600 | N06600 | ≥72 | 14–17 | 6–10 | — | — | — |
601 | N06601 | 58–63 | 21–25 | Bal. | — | — | Al 1–1.7 |
625 | N06625 | 58 min | 20–23 | 5 max | 8–10 | Nb 3.15–4.15 | — |
718 | N07718 | 50–55 | 17–21 | Bal. | 2.8–3.3 | Nb 4.75–5.5 | Ti 0.65–1.15 |
Grade | UNS No. | Tensile (MPa) | Yield 0.2% (MPa) | Elongation (%) | Hardness (HRB) | Strengthening Mechanism |
600 | N06600 | 550–760 | 245–380 | 30–45 | 75–90 | Solid solution |
601 | N06601 | 550–760 | 240–380 | 30–45 | 75–85 | Solid solution + Al₂O₃ scale |
625 | N06625 | 827–1 034 | 414–758 | 30–50 | ≤ 100 | Solid solution (Mo, Nb) |
718 (annealed) | N07718 | 965–1 100 | 550–860 | 18–25 | ≤ 36 HRC | Precip. γ″ (Ni₃Nb) |
718 (aged) | N07718 | 1 276–1 450 | 1 034–1 240 | 12–18 | 40–47 HRC | Optimised γ″ γ′ microstructure |
Grade | Max Cont. Temp. | Oxidising Atm. | Reducing Atm. |
600 | 1 093 °C | 982 °C | 1 093 °C |
601 | 1 232 °C | 1 232 °C | 1 093 °C |
625 | 982 °C | 982 °C | 704 °C |
718 | 704 °C | 704 °C | 650 °C |
Inconel sheet is manufactured and tested against a hierarchy of internationally recognised standards. The table below lists the primary governing specifications by grade and product form.
Standard | Grade | Issuing Body | Scope |
ASTM B168 | 600, 601 | ASTM International | Rolled plate, sheet, strip — nickel-chromium-iron alloys |
ASTM B443 | 625 (N06625) | ASTM International | Plate, sheet, strip — nickel-chromium-molybdenum-columbium alloy |
ASTM B906 | 718 (N07718) | ASTM International | Sheet and strip — Ni-Cr precipitation-hardenable alloy |
ASTM B670 | 718, 625 | ASTM International | Plate, sheet, strip — Ni-Fe-Cr precipitation-hardenable alloy |
ASTM A480 / A480M | All grades | ASTM International | General requirements — flat-rolled Ni-alloy plate, sheet, strip (tolerances, testing, certification) |
AMS 5596 | 625 | SAE International | Sheet, strip, plate — Ni-Cr-Mo-Cb alloy; aerospace-grade composition and property limits |
AMS 5599 | 625 | SAE International | Sheet, strip, plate — 625 annealed condition; stricter chemistry than ASTM B443 |
AMS 5664 | 718 | SAE International | Sheet, strip, plate — 718 solution annealed; aerospace and gas-turbine procurement |
AMS 5662 | 718 | SAE International | Bar, forgings, rings — 718 solution-treated; companion to 5664 for sheet |
EN 10095 / EN 10088-2 | All grades | CEN (European) | Heat-resistant and stainless flat products — European composition and property equivalents |
ISO 6207 | 625 | ISO TC 156 | Corrosion of metals; intergranular corrosion testing for Ni-Cr-Mo alloys (ASTM G28 equivalent) |
NACE MR0175 / ISO 15156 | 625, 718, 600 | NACE/ISO | Sour-service materials qualification — hardness, SCC test requirements for H₂S environments |
ASME SB-443 / SB-168 | 625, 600/601 | ASME | Pressure-vessel code adoptions of ASTM B443 / B168 for Section VIII Div.1 & 2 construction |
Grade | Primary Sectors | Representative Component Examples |
600 | Chemical, Nuclear, Heat Treatment | Retort baskets, muffle furnace liners, nuclear fuel-rod spacers, NaOH evaporator tubes, caustic concentration vessels |
601 | Industrial Heating, Petrochemical | Radiant tubes, combustion chambers, calciner liners, wire-mesh conveyor belts (oxidising atmospheres to 1 232 °C) |
625 | Offshore, Aerospace, Chemical | Subsea pipeline cladding, offshore riser overlays, aircraft engine hot-section skins, seawater heat-exchanger shells, chemical reactor linings |
718 | Aerospace, Defense, Oil & Gas | Gas-turbine casings, rocket engine combustion chambers, downhole tool housings, aircraft structural brackets, HPHT wellhead components |
Q1: What is the difference between Inconel sheet and stainless steel sheet?
Inconel sheet is a nickel-chromium superalloy (≥ 50 wt% Ni) with substantially higher nickel content than stainless steel (typically 8–14 wt% Ni). This gives Inconel sheet superior resistance to reducing acids, high-temperature oxidation, and chloride stress-corrosion cracking. However, Inconel sheet costs 4–10× more per kilogram than 316L stainless steel sheet; it is therefore selected only when stainless steel cannot meet the service requirements.
Q2: Which Inconel sheet grade is best for offshore and marine applications?
Alloy 625 (UNS N06625, ASTM B443) is the definitive standard for offshore and marine service. Its PREN (Pitting Resistance Equivalent Number) of 48–51 — calculated as Cr + 3.3 × Mo + 16 × N — exceeds the ≥ 40 threshold for seawater pitting resistance. Corrosion rates in flowing seawater are typically < 0.025 mm/yr per NACE RP0176. No other standard Inconel grade achieves this combination.
Q3: What are the standard surface finishes available for Inconel sheet?
Standard finishes include: No. 1 (hot-rolled, annealed, pickled — rough, Ra 3–8 μm); 2D (cold-rolled, annealed, pickled — matte grey, Ra 0.5–2.5 μm); 2B (cold-rolled, annealed, pickled, skin-passed — semi-bright, Ra 0.1–0.5 μm); BA (bright annealed in H₂/N₂ atmosphere — near-mirror, Ra 0.05–0.2 μm); No. 4, No. 7, and No. 8 polished finishes. Electropolishing is available for pharmaceutical and semiconductor applications.
Q4: What ASTM standards govern Inconel 625 sheet?
Inconel 625 sheet is governed by ASTM B443 (Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloy Plate, Sheet, and Strip), with ASTM A480/A480M providing general requirements for tolerances and testing. For aerospace applications, AMS 5599 or AMS 5596 apply and impose tighter compositional and property limits. Pressure-vessel construction uses ASME SB-443, which adopts ASTM B443 with ASME-specific supplementary requirements.
Q5: Can Inconel sheet be welded, and what filler metal is required?
Yes. All Inconel grades are weldable by GTAW (TIG), GMAW (MIG), SMAW, PAW, and laser-beam welding. The recommended filler wire for most grades is ERNiCrMo-3 (AWS A5.14) for Alloy 625, ERNiCrMo-4 for C-276 clad joints, and ERNiFeCr-2 for Alloy 718. Post-weld heat treatment (PWHT) is generally not required for solution-annealed grades but is mandatory for restoring full properties in aged Alloy 718 welds. Interpass temperature should be kept below 150 °C to minimise heat-affected-zone sensitisation.
Q6: What is the maximum continuous service temperature for Inconel 601 sheet?
Inconel 601 sheet (UNS N06601, ASTM B168) can be used in continuous oxidising atmospheres up to 1 232 °C (2 250 °F). This is the highest recommended temperature for any standard Inconel sheet grade. The aluminium content (1.0–1.7 wt%) forms a tightly adherent Al₂O₃ layer that reinforces the chromium oxide scale and prevents spalling during thermal cycling, giving 601 superior oxidation life compared to Alloy 600 above 950 °C.
Q7: Does Inconel sheet comply with ASME pressure-vessel code?
Yes. Inconel 600 sheet (ASME SB-168), Inconel 625 plate (ASME SB-443), and Inconel 718 (ASME SB-670) are listed in ASME BPVC Section II Part B with published allowable stress values for use in Section VIII Division 1 and Division 2 pressure vessels. The ASME SB- prefix indicates that the material has been adopted from the corresponding ASTM B- standard with any supplementary ASME requirements applied.
