These nickel chromium base alloys are used extensively in applications where heat resistance and/or corrosion resistance is required. In some members of the group, where conditions are less demanding, some nickel is replaced by iron to decrease the overall cost.

Metals fail at high temperatures by both oxidation (scaling) and through a loss in strength. Alloys in this class are designed to resist failure from both of these mechanisms. Nickel alloys are not suitable for high temperature sulphur rich environments.

Where corrosion resistance is significant, molybdenum is used as an alloying addition in nickel chromium based alloys.

This group of alloys are frequently sold under trade name specifications but most are listed in the Unified Numbering System. Common trade names are HASTELLOY, INCOLOY, INCONEL, NICROFER, NICROM and NIMONIC.

The more recentnickel chromium base alloys in these groups also have a wide range of ancillary elements added to give special properties – some of these can be quite complicated and require very close control over composition and heat treatment.