Inconel 601 Round Bar (UNS N06601): Properties, Sizes and Where It's Used

Quick answer: Inconel 601 (UNS N06601) is a nickel-chromium alloy with about 23% chromium plus aluminium, which gives it outstanding oxidation resistance up to roughly 1200 °C and useful strength to ~1000 °C. As a round bar it is normally supplied bright-peeled or centreless-ground in diameters from about 6 mm to 300 mm, and used for furnace parts, heat-treat fixtures, radiant tubes and aerospace / chemical components. When you order, specify UNS N06601, the diameter and tolerance, annealed (bright) condition, and the standard — usually ASTM B166 / ASME SB166. The black marker "N06601" on our stock is exactly that UNS grade call-out.

What Inconel 601 is (and why the "N06601" mark)

UNS N06601 is the unified numbering for Inconel 601. The "N" prefix means nickel alloy; the "06601" is the grade. It is a solid-solution strengthened alloy whose key addition is aluminium (1.0–1.7%), which forms a tight, self-healing Al₂O₃ scale that resists spalling in cyclic heat.

Nominal composition:

Why 601 and not 600 or 625

For pure high-temperature oxidation resistance, 601 beats 600; for strength and seawater, 625 is the better call.

Inconel 601 round bar: sizes and condition

We stock bright bars in the common engineering diameters and supply larger peeled and ground sizes to order. The bar in the photo is bright-peeled stock marked "N06601" for grade identification.

Mechanical properties (annealed)

601 is not age-hardenable like 718 or X-750 — its strength comes from solid-solution strengthening, so there is no precipitation-hardening heat treatment to specify. For the age-hardening family, see our Inconel 718 heat-treatment guide.

Temperature and oxidation behaviour

• Continuous service: up to ~1150–1200 °C in air, with an adherent scale.
• Cyclic heating/cooling: the aluminium oxide scale resists spalling far better than the chromium-only scale of 600.
• Carburization / nitriding: 601 resists high-temperature carburizing atmospheres better than most austenitics.
• Creep: usable for load-bearing furnace parts up to ~1000 °C; above that, design for low stress.

Typical applications

• Furnace muffles, radiant tubes, retorts and trays.
• Heat-treat baskets, fixtures and radiant-cup burners.
• Aerospace and gas-turbine exhaust components.
• Chemical and petrochemical high-heat hardware.
• Kiln and incinerator parts.

Machining and welding notes

• Machinable like other nickel alloys: rigid setup, low speed, positive rake, plentiful coolant; it work-hardens, so avoid dwell.
• Weldable with matching 601 filler (ERNiCrFe-11) or overalloyed 625 filler for some joints; keep clean and use low heat input.
• Bars are usually supplied annealed and ready to machine — no post-weld heat treatment is required for corrosion, though stress relief helps dimensional stability.

Inconel 601 bar RFQ checklist

1. UNS N06601 (confirm not 600/625 by application).
2. Diameter and tolerance (e.g. 50 mm h9, or centreless-ground).
3. Condition: bright-peeled or ground.
4. Length: random mill length or cut-to-length, quantity.
5. Standard: ASTM B166 / ASME SB166, with MTC per mill-test-certificate reading.
6. If forged sizes are needed rather than rolled bar, see our forged round billets.

FAQ

Q: Is "N06601" the same as Inconel 601? A: Yes. N06601 is the UNS (Unified Numbering System) grade code for Inconel 601; you will see both used on mill certs and on the bar itself.

Q: Can 601 be heat-treated to get harder? A: No — it is solid-solution strengthened, not age-hardenable. Strength comes from chemistry and cold work; there is no precipitation-hardening step like Inconel 718.

Q: 601 or 600 for a furnace fixture? A: For continuous or cyclic high heat (above ~900 °C), 601 is the safer choice because of its aluminium oxide scale. For lower-temperature corrosion service, 600 is often enough and cheaper.

Q: What diameter bar can I get? A: Standard bright bar runs from about 6 mm to 120 mm from stock, with larger peeled and ground diameters to ~300 mm on order; weight per metre follows the alloy weight formula.

Q: Does 601 need PWHT after welding? A: For corrosion and oxidation service, no post-weld heat treatment is required; a stress-relief anneal is optional for dimensional stability of machined parts.