Bohler Uddeholm Blade Steels

[Alpha Knife Supply]

At Blade Show this year Bohler Uddeholm (BU) introduced some of their blade steels to North America. The steels are:
• N680 - Bohler stainless nitrogen steel - extreme corrosion resistance
• N690 - Bohler stainless steel
• Elmax - Uddeholm stainless steel - particle metallurgy
• M390 - Bohler stainless steel - particle metallurgy

N680 is a steel with extreme corrosion resistance. The nitrogen in the steel helps resist pitting from salt water and sweat. It is not as corrosion resistant as H1 in salt water spray tests, but it is far superior to 440C. It has two big advantages over H1: it is affordable and it is available.
N680 Information
N680 Heat Treat Information
N680 Data Sheet

N690 is a tough stainless steel. It has cobalt which helps prevent cracking and a small shot of vanadium for grain refinement. It is a good steel for knives that will see tough use. I spoke to Jerry Hossom at Blade show about N690. He said he chose this steel for his factory collaborations because of its toughness and resistance to cracking. N690 is similar to VG10 from Japan.
N690 Information
N690 Heat Treat Information
N690 Data Sheet

Elmax is a powder metallurgy stainless steel. In the heat treat information we show three different austenitizing temperatures and tempering curves. The 2100° recipe provides the highest edge holding. The 1920° recipe provides the best toughness. The 2010° recipe is a compromise of edge holding and toughness
Elmax Information
Elmax Heat Treat Information
Elmax Data Sheet

M390 is another powder metallurgy stainless steel. It's Bohler's high end stainless steel. The edge holding and toughness are very good.
M390 Information
M390 Heat Treat Information
M390 Data Sheet

Paul Bos and Peters Heat Treating are ready to provide heat treating services for the steels.

Knifemakers have been testing and working with the steels for a few months. I hope they will add their comments to this thread.

 

[John L]

As I make folders only I sure wish heat treat specs were given for Rockwell hardness below50-53 as I would like to make springs....hardly ever happens. :thumbdn:

 

[Jon Walker]

Everyone needs to try n680 it is a crazy steel! The knife I made from it cuts very well. I think it is an ideal steel for hunting knives since it is so stainless and holds a great edge.

In my experience it worked easily and satin finished easily as well. I am excited for the BU steels!

I am pretty sure that you can temper the hardness down for springs, however, these steels are designed to be hard and durable with small grain which makes them great for folder blades.