Bulletin No. 14 - Metal Specifications

Metal Specifications

Get it Right or Get the Wrong Stuff
When ordering material, it is important to use a complete designation that accurately describes that material. For example, the high strength precipitation hardening stainless steel designation, 17-4PH, comes from the commercial designation used by the inventor, Armco Steel. Inconel and Hastelloy are trade names commonly associated with two specific alloys, however these names can describe a family of alloys. Using just that “family” name can lead to costly errors. Any name can be given to an alloy, but if the UNS # or EN is given then it will meet the specific chemical composition requirements unique to that alloy.

We need also remember that while metal designations describe materials, these designations do not include product form or quality level.
Grain flow produced by forging influences its properties


Product Form

To specify the correct material, chemical composition alone is not enough. The product form is also a requirement because product form (casting forging rolled plate, tube etc.) might have an effect on end use, service life and availability. See photo.