Toughness and edge retention of Damascus

[awestib]

Hi guys,
I am not a knife maker, not even as a hobby but I find forging and hardening/tempering a blade fascinating and I want to learn as much as I can, just for fun! And who knows, maybe one day ...

My question is, a bigger camp damascus knife made from 1084 and 15N20, does it have to be differentially heat treated/tempered or Is it the 1084 that gives the edge retention and 15N20 that gives the toughness if it is hardened all through and tempered to the right hardness? So with this combination of steels, no need for differential treatment?

This question relates to a WIP thread that I saw by Nick Wheeler and it seems that this is what was done to the blade!

Thanks in advance for all your input!!

 

[SteelSlaver]

You can harden the whole blade, that converts all the steel to martinsite, weather damascus or say just 1095, 5160, 1080,15n20, then if you want some more "toughness" draw the spine of the knife to a higher temper like 800f. This will give it a spring like temper in this area. While 15n20 would be somewhat tougher because of the nickel in it, the reason 1080 and 15n20 makes a great damascus mix is because they both harden very similarly and both will hold a very good edge. Some people are fans of edge hardening, which converts the edge to martinsite and leaves the spine mostly pearlite. But, most metallurgist contend that spring tempered martinsite is as tough or tougher. Plus you do not have a conversion zone in the blade. Clay tempering gives much the same result with the hamon being the conversion zone. Most do this for the wonder and beauty of the hamon rather than any superiority in toughness.

Some will debate the edge hardening vs spine temper toughness factor. I will say that neither is bad when well done and can both make excellent knives. Both methods have the ability to pass the bending portion of the ABS test. But in either case you want the edge to be fully hardened and tempered to the correct hardness for the blades use. No mater what steel or steels the knife is composed of.