ApexUltra 5x50x250mm

A new steel developed specifically for handmade knives.

ApexUltra is a steel truly worth of handcrafted knives. It is a low alloy design that is forgeable, forge-weldable, and its fine carbides make the steel relatively easy to finish and sharpen. With its high purity and well-balanced alloy composition it has the highest toughness of all knife steels tested so far in the 66+ HRC range along with excellent edge retention.

Which knives is ApexUltra best suited for?

With its combination of high hardness and toughness, ApexUltra works very well in knives with thin, acute edges. Culinary knives, razors, and carving knives are examples of good applications.  

Can I forge and forge-weld ApexUltra?

Yes, the steel is forgeable as well as forge-weldable. The forging and forge-welding behaviour can be described as similar to 52100 / 1.3505 / 100Cr6 or F2 / 1.2562. So, this is not a steel recommended for beginners, but it is perfect for anyone seeking the next level of performance in carbon steel knives.

How is it possible to develop a new steel today?

Actually, there has been little research on new carbon steels for fine cutting knives as this is a not a field that the tool steel industry is interested in. The focus of the knife steel development has been in the stainless sector with optimizing slicing edge retention rather then fine edges for push cutting. Consequently, there are many ideas left explored in the area of steels that are well suited for bladesmiths to forge into fine cutting knives.  


Is ApexUltra easy to sharpen?

Despite the high hardness, it is rather easy to sharpen and does not require special diamond sharpening tools. Whetstones and leather strops are effective for knife care, and with the fine microstructure very keen edges can be achieved. A honing rod is only recommended for the lower hardness levels and should always be used with care not to damage the edge. Experienced sharpeners have, however, successfully used very fine honing rods up to high hardnesses as well.

How can I heat treat ApexUltra?

There will be a variety of recommended heat treatment protocols for you to chose from once the batch has been delivered to us and we have had the chance to test this exact batch. We will make sure that there is a recommended procedure for different hardness levels and applications, and with Larrin’s new video about heat treating in the gas forge out, we are even playing with the thought of adding a recommended procedure for gas forge heat treatment. Although we strongly recommend a more precise method for heat treating any steel. ApexUltra is designed to have balanced hardenability: high enough that full thickness knives will harden in oil without using a risky water quench, yet low enough in hardenability that the steel is easy to anneal by placing in slow cool media like vermiculite or perlite.  

HOT WORKING
•    Temperature : 800-1120°C (1475-2050°F) WARNING : DON’T HEAT ABOVE 1120°C (2050°F) ! STEEL MAY GET IRREVERSIBLY DAMAGED.
 
ANALYSIS

C    W    V    Cr    Mn    Si
1.25%    2.60%    0.40%    1.50%    0.30%    0.35%

AUSTENITIZING
•    Temperature : 780-880°C (1435-1615°F)
•    Holding time : 10 minutes
•    Medium : Accelerated oil
 

 
NORMALIZING
•    Temperature : 950°C (1750°F)
•    Holding time : 15 minutes
•    Air cool below 600°C (1100°F)


GRAIN REFINING
•    Quickly heat up to 790°C (1450°F)
•    Holding time : 10 minutes
•    Air cool.
THIS OPERATION CAN BE PERFORMED 2 TO 3 TIMES TO GET SMALLER AUSTENITE GRAIN SIZES.


ANNEALING
•    Heat to 790°C (1450°F)
•    Holding time : 10 to 30 minutes
•    Slow cooling in steps of 250°C (475°F) per hour until 590°C (1100°F), then air cool to room temperature.

YOU CAN ALSO PLACE THE PIECE IN A SLOW COOL MEDIA LIKE VERMICULITE.
 
DEEP FREEZE (NOT MANDATORY)
•    Immediatly after quench.
•    Medium : dry ice or liquid nitrogen
•    Holding time : 30 minutes

TEMPERING
•    Temperature : 150-240°C (300-460°F)
•    Holding time : 2 cycles of 1 hour each.