Inconel® Nickel-Chromium Alloys

Technical overview

"Inconel" is a family, not one material. Alloy 600 (UNS N06600) is a nickel-chromium-iron alloy that can only be strengthened by cold work. It is widely used in furnace and heat-treating equipment such as retorts, muffles and wire belts.

Alloy 625 (UNS N06625) is a solid-solution Ni-Cr-Mo-Nb alloy with almost no attack in seawater and resistance to a wide range of severe corrosive environments. Alloy 718 (UNS N07718) is precipitation-hardened for high strength; it is referenced in AMS 5596/5597 and produced for oil-field use under NACE MR0175.

Technical properties

Typical or specified values for the named grade from the cited source. Actual values depend on temper, size and the producing mill — rely on the mill certificate for your lot.

Forms

Typical industry forms for this material. They are not a stock list — form, size and availability are confirmed per enquiry.

• Round bar
• Plate & sheet
• Pipe & tube
• Wire
• Forgings & rings
• Fasteners

Applications & industries

• Furnace retorts, muffles and heat-treating fixtures (600)
• Seawater and chemical-process components (625)
• High-strength fasteners and rotating parts (718)
• Oil and gas components to NACE MR0175 (718)

What to specify when requesting a quote

1. 1Alloy number and UNS (600 / 625 / 718 or other)
2. 2Heat-treatment condition and any AMS / NACE requirement
3. 3Whether trademarked INCONEL® material is mandatory
4. 4Grade and the standard it must conform to (ASTM, EN, IS, UNS or your drawing)
5. 5Form and dimensions — thickness or diameter, width, length and tolerances
6. 6Approximate quantity, and whether the requirement is one-off or recurring
7. 7Intended application, so the grade can be cross-checked before quoting
8. 8Documents required — e.g. mill test certificate, chemical analysis, certificate of conformity
9. 9Delivery city / site and the date you need material by

Documents buyers may request

• Mill test certificate

  e.g. EN 10204 type 3.1 inspection certificate, where the producing mill issues one

• Chemical analysis report

  heat / lot composition against the specified grade

• Certificate of conformity

  confirming the material meets the ordered standard

• Heat / lot traceability

  heat numbers marked on material and documents

• Dimensional inspection report

  for cut-to-size or machined material

• Safety Data Sheet (SDS)

  especially for lead, beryllium-, cadmium- or lead-bearing products

Which documents can be provided depends on the source mill and is confirmed with each quotation.

Frequently asked questions

Sources & technical references

1. INCONEL® alloy 600 technical bulletin — Special Metals Corporation. Checked 2026-10-14.
2. INCONEL® alloy 625 technical bulletin — Special Metals Corporation. Checked 2026-10-14.
3. INCONEL® alloy 718 technical bulletin — Special Metals Corporation. Checked 2026-10-14.
4. ASTM B168 — Ni-Cr-Fe Alloy Plate, Sheet and Strip — ASTM International. Checked 2026-10-14.Full standard is paywalled — only the public abstract and scope on astm.org were read. Composition tables were not accessed.
5. ASTM B446 — Ni-Cr-Mo-Nb Alloy (UNS N06625) Rod and Bar — ASTM International. Checked 2026-10-14.Full standard is paywalled — only the public abstract and scope on astm.org were read. Composition tables were not accessed.
6. ASTM B637 — Precipitation-Hardening Nickel Alloy Bars, Forgings and Forging Stock — ASTM International. Checked 2026-10-14.Full standard is paywalled — only the public abstract and scope on astm.org were read. Composition tables were not accessed.