Oil vs. adjusted temper?

[AA Forge]

I was wondering if any one had any info on this subject.

Say you take a piece of 1095 and forge two knives from it, and you take one and quench it in Parks#50 quenching oil and achieve a full 65-66 Rockwell, and than temper it down to a 58 Rockwell. The other one you quench in say peanut oil, or mineral oil and only achieve a 60 Rockwell, but you adjust your tempering temps and finish up with the same 58 Rockwell. My question is, evan thow they are the same Rockwell, would there be any real difference in the performance of one over the other?

Thanks ahead of time,
Adam

 

[Don Hanson III]

The blade that reached full hardness will out perform the other.

 

[Russ Andrews]

A fully quenched, and properly tempered blade will be
superior to one which was underhardened.

The underhardened blade will have a much higher percentage
of pearlite (less martinsite) and will not be capable of best
edge properties.

 

[AA Forge]

Thanks guys, thats what I needed to know!

Adam,

 

[cotdt]

In reality though, with 1095 you either get the full 65-66 rc or ~40 rc. With thicker stock 1095 that's been oil quenched, you often get an unintended hamon. The thinner section is fully hardened, while the thicker spine section is soft, with very little in between. With canola oil the transition point seems to be at around 1/8" thickness, and sections thicker than that are soft.

 

[SteelSlaver]

The difference if you could control the process enough to get the similar 58 RC reading would be that the fully hardened and tempered knife would have a very high % of martensite where the other would contain a lot of pearlite. That difference in the amount of martensite would make a big difference in the properties of the steel. As often pointed out there is a lot more to steel than how hard it is. Wear resistance, deformation resistance, impact resistance are all big to.
I worked with steel a lot of my life, it seemed so simple, then I started making knives and found out how little I knew. In the past 5 or so years I have read all kinds of books, and several forums almost daily. One of the first things I learned is how much bad information there was and how much I had to unlearn. Still learning.