The most important thing about Inconel from a specs point of view is its ability to maintain strength and resist oxidation at high enough temperatures that would otherwise cause other stainless steels to become soft or scale. one heat limit. Grade 625 tops out well below grade 601. The chart below lines up the maximum service temperature for every Inconel and Incoloy grade Kalpataru Piping supplies, so you can shortlist a grade for a spec or RFQ in one pass. For the fuller picture on composition, general properties, and melting point, start with our Inconel material grades, properties, and composition guide, then come back here for the temperature-specific comparison.
Inconel Maximum Service Temperature: All Grades (Master Chart)
|
Grade |
UNS No. |
Approx. Max Continuous Service Temp |
Notes |
|
Inconel 600 |
N06600 |
Up to ~1,000–1,150°C (oxidation); high strength retained to ~650°C |
Strength and oxidation limits differ; see “Why Different Sources Quote Different Max Temperatures” below |
|
Inconel 601 |
N06601 |
Up to ~1,090–1,150°C |
Excellent oxidation resistance; good creep strength above 500°C |
|
Inconel 617 |
N06617 |
Up to ~1,100°C |
High-temperature strength and oxidation resistance |
|
Inconel 625 |
N06625 |
~980°C (continuous service) / up to 1,093°C (strength retention, per source) |
See “Why Different Sources Quote Different Max Temperatures” for why figures vary by source |
|
Inconel 690 |
N06690 |
Effective to ~1,000°C+ |
Chosen mainly for chloride and high-temperature water SCC resistance |
|
Inconel 718 |
N07718 |
Good strength and toughness up to ~650–700°C |
Precipitation-hardened; loses strength above this range |
|
Inconel X-750 |
N07750 |
Good strength below ~980°C |
Common in springs, fasteners, gas turbine components |
|
Incoloy 800 / 800H / 800HT |
N08800 / N08810 / N08811 |
Strength maintained above ~600°C; oxidation-resistant to ~1,100°C |
800H/800HT variants improved for creep service |
|
Incoloy 825 |
N08825 |
General service typically below ~550°C |
Selected for corrosion resistance, not high-temperature strength |
Strength Retention vs Temperature (Inconel 600 and 625)
A max temperature figure only tells you when a grade starts to fail. It does not tell you how much strength you still have at 400°C versus 700°C, which is the number that actually drives a wall-thickness or fastener-torque calculation. The table below tracks tensile and yield strength across five temperature points for Inconel 600, and flags where the same data needs to be pulled for Inconel 625.
|
Temp (°C) |
Inconel 600 Tensile (MPa) |
Inconel 600 Yield (MPa) |
Inconel 625 Tensile (MPa) |
Inconel 625 Yield (MPa) |
|
316 |
624 |
214 |
See mill certificate / ASTM B446 |
See mill certificate / ASTM B446 |
|
427 |
609 |
203 |
See mill certificate / ASTM B446 |
See mill certificate / ASTM B446 |
|
538 |
579 |
183 |
See mill certificate / ASTM B446 |
See mill certificate / ASTM B446 |
|
649 |
448 |
117 |
See mill certificate / ASTM B446 |
See mill certificate / ASTM B446 |
|
760 |
103 |
28 |
See mill certificate / ASTM B446 |
See mill certificate / ASTM B446 |
Frequently Asked Questions
What is the maximum temperature Inconel can withstand?
Depending on the grade, Inconel can withstand temperatures from about 650°C to over 1,100°C.
Which Inconel grade has the highest temperature resistance?
Inconel 601 and Incoloy 800HT are suitable for continuous service above 1,100°C in oxidizing conditions.
What is the difference between Inconel 625 and Inconel 718 in terms of temperature limits?
Inconel 625 can handle around 980°C, while Inconel 718 is generally limited to approximately 650–700°C.
Why do different sources give different maximum temperatures for the same Inconel grade?
Because temperature limits depend on oxidation resistance, strength retention, and continuous or intermittent service.
At what temperature does Inconel 718 lose its strength?
Inconel 718 generally maintains good strength up to around 650–700°C, after which its strength decreases.
Is Inconel better than stainless steel at high temperatures?
Yes, Inconel generally provides better high-temperature strength and oxidation resistance than standard stainless steel grades such as 304 and 316.
Can Inconel 600 be used continuously above 1,000°C?
Yes, Inconel 600 can provide oxidation resistance above 1,000°C, although its load-bearing strength is lower at these temperatures.
Which Inconel grade should I choose for a furnace or heat exchanger application?
For furnaces, Inconel 601 or Incoloy 800HT are suitable for high temperatures. For corrosive heat-exchanger service, Inconel 625 or Incoloy 825 may be preferred.
