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Good morning everyone, this is Michael with Michlin Metals. Guess what today is? Today is talk about Nickel and Cobalt Alloys day. Who hooo!!! Now before we jump in, please remember to check out our previous videos if you’ve missed them! Also, if you find these videos interesting, please subscribe, hit that little MMI button right there and subscribe. Now onto Nickel and Cobalt!

Today we start a series of videos that introduce two groups of metals that are not iron based like the stainless heat and corrosion resisting steels we discussed earlier. We saw that increasing other elements like nickel, chromium, and molybdenum in a steel boosted the corrosion and temperature performance.  So at some point, metallurgists no longer consider the alloy an iron based  “steel”.

And with that said ….we introduce you to Nickel  and Cobalt  alloys…..

We will divide these solely by the Unified Numbering System (UNS) chemistry category. The UNS system is a combined effort of SAE (Society of Automotive Engineers) and ASTM (American Society for Testing and Materials). Both of those differ from the Aerospace Material Specifications (AMS Specs).

Nickel and Nickel alloys have a UNS chemical composition designation of  N followed by five numbers and the Cobalt alloys R followed by five numbers.

Some proprietary types may not have been assigned a UNS designation.

The element that we consider to be the “base” just means that it  is  the major alloying element in that particular metal alloy. Often these alloys contain both nickel and cobalt in addition to other elements.  The Nickel alloys more nickel than Cobalt and in Cobalt alloys more cobalt than nickel.

OK, now that we have established our “rules” we can discuss a couple grade names. In the Nickel base category we have alloys with  common proprietary names like Monel, Incoloy, Inconel, Haynes, Waspaloy, Nimonic, and Hastelloy as well as generic versions designated only by the “alloy number” For instance, we have Nickel 200/201, Monel 400, Monel 405, or K500, we have Inconel 600/625/718/800 H/HT/825. There’s Hastelloy grades C22/C276 and Hastelloy X. There’s many more but for now, that’s a good start.

For example, Inconel 600 named products would require the trade name product and alloy 600 would be a generic alloy. Much like Tylenol and generic acetaminophen at the drugstore.

In the Cobalt base we have trade names of Haynes and Stellite, L605, and MP35N. Cobalt is also extremely expensive so hang onto your hats if you ever need to buy this material.


All these alloys are generally higher cost than ferrous heat and corrosion resistant types but as I just mentioned, especially cobalt. Typical applications are found where higher temperatures or the corrosion environment favor these alloys over the heat resistant stainless types. Most of these alloys cannot be strengthened by heat treatment but several can be strengthened by a precipitation hardening treatment.

Specifications have more requirements than just a chemical composition so always, always … check the specs! So this wraps up our brief discussion of Nickel and Cobalt Alloys. Stay tuned as we’ll dive deeper into each grade for a much greater discussion around specific grade attributes.

Thanks for watching! Don’t forget, if you made it this far, subscribe, please. Click here. If you missed any of the previous videos, click here. Thanks for tuning in, this is Michael with Michlin Metals. Out!