One more question

C

CDH

Joined
Jun 8, 2007
Messages
283
Another thing I have been wondering about and unable to find an answer to in the archives...

In comparing methods for a soft backed blade, I see several processes that should result in 2 end results. Correct me if I an wrong, but:

First, the edge and clay quench methods would result in a hardened edge with a spine primarily of ferrite.

Second, the fully hardened blade with a torch tempered spine would result in a hardened edge with a heavily tempered martensite spine.

What is the practical difference between the two in terms of impact resistance and flexibility before permanent deformation?

The reason I ask is because I have 2 pieces of steel (1095 and 5160) waiting for my next learning experience :D ...both 1/4" thick and destined for camp blades. I was considering trying one of these methods at the same time.
 
Spine structure - if the edge only is hardened [spine never above critical temp] the spine will have the original structure which will be spheroidized or pearlite. If the entire blade gets above critical and the blade is edge quenched or clay is used the spine will be fine pearlite [not ferrite].A tempered spine will take a bit more skill but will have a stronger spine and will not permanently deform as fast as the others.
 
Your first learning experience is that 1095 is a shallow hardening steel and 5160 is deep hardening. With a clay coated blade or an edge quench, the 1095 will have a martensitic edge and a pearlitic spine. Done the same way, 5160 will have an all martensitic blade with varying degrees of hardness due to the auto- temper. A draw with a torch will make the differential even larger. If you want two different structures, use the 1095. For a single structure, use 5160. As to which will perform better, it depends on the desired tolerance. The 1095 with a pearlite spine will take a big bend before breaking. The 5160 with a differential temper will be more springy, but will have a somewhat softer edge and more tendency to break at the extreme of distortion. For a sword use the 1095. For a camp knife/chopper, use the 5160.
Stacy
 
also there is the hamon that results from a clay quench that is very desirable aesthetically.
 
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