Inconel® is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys.
Inconel® alloys are one of the most versatile metals available. Thanks to their high performance and superior properties, they are used in a wide range of industries.
They are a natural choice in the automotive, aerospace, marine, oil and gas industries because they are specifically optimized to withstand some of the most demanding manufacturing conditions.
Types of Inconel® alloys
Although the composition of Inconel® alloys varies widely, they all consist of nickel and chromium as primary elements. These special metals are not to be confused with duplex stainless steel, austenitic stainless steel or any other type of stainless steel alloy. Below is a quick overview of the different types of Inconel® alloys.
Inconel® 600
This nickel-chromium alloy is highly resistant to a wide range of corrosive elements. It does not succumb to general oxidation or stress corrosion corrosion by chloride ions, even at extreme temperatures.
Inconel® 601
Inconel® 601 contains nickel, chromium and aluminum. The addition of aluminum gives it exceptional mechanical properties even in high temperature environments.
Inconel® 625
Inconel® 625 contains nickel, chromium, molybdenum and niobium. The reaction between molybdenum and niobium hardens the alloy's matrix microstructure, increasing its overall tensile strength. It is what makes this nickel-based alloy highly resistant to the corrosive elements found in harsh environments.
Other well known names for Inconel® 625 are Haynes 625, Nickelvac 625, Nicrofer 6020, Altemp 625 and Chronic 625.
| Property | 21 °C | 204 °C | 316 °C | 427 °C | 538 °C | 649 °C | 760 °C | 871 °C |
| Ultimate Tensile Strength /Mpa | 992.9 | 923.9 | 910.1 | 910.1 | 896.3 | 820.5 | 537.8 | 275.8 |
| 0.2% Yield Strength /MPa | 579.2 | 455.1 | 434.4 | 420.6 | 420.6 | 413.7 | 406.8 | 268.9 |
| Elongation % | 44 | 45 | 42.5 | 45 | 48 | 34 | 59 | 117 |
| Coefficient of Thermal Expansion µm/m⁰C | - | 13.1 | 13.3 | 13.7 | 14 | 14.8 | 15.3 | 15.8 |
| Thermal Conductivity /kcal/(hr.m.°C) | 8.5 | 10.7 | 12.2 | 13.5 | 15 | 16.4 | 17.9 | 19.6 |
| Modulus of Elasticity/ MPa | 2.07 | 1.93 | 1.93 | 1.86 | 1.79 | 1.65 | 1.59 | - |
Inconel® 625 specifications
Welding consumables
Inconel® 690
Unlike other metal alloys of the family, Inconel® 690 is made of high chromium and nickel. The use of high chromium makes this particular variant of the metal alloy highly resistant to the corrosive conditions synonymous with aqueous environments. Its high corrosion resistance also makes it resistant to the sulfidation that occurs in high-temperature environments.
Inconel® 718
The structure and reaction of Inconel® 718 are very different from the other metals in the family. This nickel-based superalloy consists of nickel and chromium, in addition to significant amounts of molybdenum, niobium and iron. It also contains traces of aluminum and titanium. The combination of these alloying elements makes Inconel® 718 very strong, flexible and resistant to cracking after welding.