PMPA Craftsman Cribsheet #138: ISO Material Groups: Heat-Resistant Alloys
Published March 31, 2025
By David Wynn, Technical Services Manager, PMPA
Heat-resistant alloys, also known as super alloys, are used in mission-critical applications. When parts can’t fail, they are often made from these alloys. This group is one of the most difficult and most expensive to machine. High-temperature alloys are typically broken down into four categories (occasionally five, because some manufacturers list titanium and titanium alloys separately).
This list is a good starting point for understanding how to determine suitability for various applications. ISO material groups are what you use to identify the material you are machining when selecting carbide inserts.
Heat-resistant alloys are so varied that it is difficult to give a generalized starting point for speeds and feeds. It is best to work with tooling manufacturers with the latest data to find a starting point. Each cutting operation is different, and it will take experimentation to find the combination of tools, coatings and process variables that best fit your process.
Author
David Wynn
David Wynn, MBA, is the PMPA Technical Services Manager with over 20 years of experience in the areas of manufacturing, quality, ownership, IT and economics. Email: gro.apmp@nnywd — Website: pmpa.org.