Inconel 600 Plates vs Inconel 601 Plates: Overview
Inconel 600 (UNS N06600) and Inconel 601 (UNS N06601) are nickel-chromium alloys produced as plate and sheet for high-temperature and corrosive service. Inconel 600 plate offers higher strength and better cold working properties, making it a general-purpose choice for high-temperature and corrosive environments. Inconel 601 plate, with its higher chromium content and aluminum addition, excels in extreme high-temperature conditions where oxidation, carburization and sulfidation resistance are the dominant requirements. In essence, Inconel 601 trades some room-temperature strength for significantly improved high-temperature and scaling performance.
Chemical Composition Compared
Inconel 600 plate typically contains nickel 72.0% min, chromium 14.0-17.0%, iron 6.0-10.0%, carbon 0.15% max, manganese 1.0% max, silicon 0.50% max, sulfur 0.015% max and copper 0.50% max.
Inconel 601 plate typically contains nickel 58.0-63.0%, chromium 21.0-25.0%, iron as balance, carbon 0.10% max, manganese 1.0% max, silicon 0.50% max, sulfur 0.015% max and copper 1.0% max, with aluminum present as a deliberate strengthening and scaling-resistance addition.
The higher chromium and the aluminum in 601 allow it to form a denser, more stable oxide film at high temperature, which is the root of its superior oxidation and sulfidation resistance.
Mechanical and Physical Properties
Annealed Inconel 600 plate typically shows a minimum tensile strength of about 655 MPa, yield strength of about 310 MPa and elongation of about 40%, with a density near 8.47 g/cm3 and a melting point around 1413°C. Inconel 601 plate typically shows a minimum tensile strength of about 550 MPa, yield strength of about 205 MPa and elongation of about 30%, with a density near 8.1 g/cm3 and a melting point around 1411°C.
Both alloys are nonmagnetic and perform well from cryogenic temperatures to high-temperature service. Inconel 600 retains strength up to approximately 1150°C, while Inconel 601 provides exceptional scaling resistance in continuous high-temperature service up to about 1200°C.
Corrosion and Scaling Resistance Compared
Both alloys resist many common corrosive environments. In chloride stress corrosion cracking service, Inconel 601 is slightly superior to Inconel 600 thanks to the synergistic effect of chromium and aluminum. In sulfur-bearing environments such as petroleum refining and coal chemical service, 601 plates again show better sulfide corrosion resistance because of their higher chromium and aluminum levels.
Inconel 601 also demonstrates better metallurgical stability under high-temperature thermal cycling and thermal stress, which is why it is preferred for furnace linings, radiant tubes and high-temperature fixtures that see severe oxidizing-reducing atmosphere swings.
Typical Applications
Inconel 600 plate: equipment linings, heat exchanger components, furnace structures, reaction vessels, chemical and nuclear process equipment, and heat treatment fixtures where strength retention to about 1150°C and chloride stress corrosion cracking resistance are needed.
Inconel 601 plate: high-temperature heat treatment furnaces, industrial combustion systems, petrochemical cracking units, aerospace hot-end components, radiant tubes and ultra-high-temperature fixtures exposed to oxidizing, carburizing or sulfidizing atmospheres.
Equivalents and Specification Notes
Inconel 600 plate corresponds to W.Nr 2.4816, JIS NCF 600, BS NA 13 and EN NiCr15Fe. Inconel 601 corresponds to W.Nr 2.4851, JIS NCF 601, BS NA 49 and EN NiCr23Fe. Both are commonly supplied to ASTM B168 / ASME SB168, and 601 sheet to AMS 5540. Confirm the required temper, hardness and dimensional tolerances with the supplier for each project.
FAQ
Q: Which is stronger, Inconel 600 or Inconel 601 plate?
A: Inconel 600 has higher room-temperature strength, with typical minimum tensile strength of about 655 MPa versus about 550 MPa for 601 in the annealed condition.
Q: Is Inconel 601 plate magnetic?
A: No. Inconel 601 is a nonmagnetic nickel-chromium alloy, which is important for certain instrument and electronic applications.
Q: Why is Inconel 601 better at high temperature than 600?
A: Its higher chromium content combined with aluminum forms a denser and more stable oxide film, giving superior resistance to oxidation, carburization and sulfidation at extreme temperatures.
Q: Can Inconel 600 plate be used in chloride environments?
A: Yes. Inconel 600 has good resistance to chloride ion stress corrosion cracking, and 601 is slightly superior in this respect due to its chromium-aluminum synergy.
Q: What standards cover these plates?
A: ASTM B168 / ASME SB168 covers both Inconel 600 and 601 plate and sheet; AMS 5540 covers Inconel 601 sheet for aerospace applications.
Q: Which should I choose for a furnace lining?
A: For continuous high-temperature furnace linings exposed to oxidizing or carburizing atmospheres, Inconel 601 is usually the better choice because of its superior scaling resistance.
