HRC Database

[VandymanG]

Sigh stumbled onto this thread and thought hmm maybe this will help sort out my confusion.

Nope! Just reinforced my confusion with HRC and bevel angles.

Sigh still optimistic that I will figure it out some day.

[Makunochimaster]

Anyone tested hardness s35vn on new tenacious/persistence/ambitious?

[Traditional.Sharpening]

Sigh stumbled onto this thread and thought hmm maybe this will help sort out my confusion.

Nope! Just reinforced my confusion with HRC and bevel angles.

Sigh still optimistic that I will figure it out some day.

I'd personally ignore HRC numbers if I were you, it's best reserved as a QC step in production. It is not a measure of quality so much as a means for the manufacturer to gauge whether their batch has been heat treated as intended. If they test them and they don't have the expected range then they know somewhere, something went wrong.

[kennbr34]

Sigh stumbled onto this thread and thought hmm maybe this will help sort out my confusion.

Nope! Just reinforced my confusion with HRC and bevel angles.

Sigh still optimistic that I will figure it out some day.

Here's a good post by Larrin Thomas that should shed a little light on the matter
https://knifesteelnerds.com/2018/08/27/ ... stability/

Kind of a basic summary... Edge stability can be thought of as the edge's resistance to deformation. "Deformation" covers both things like denting and rolling, and also chipping and cracking. The article basically explains that as a steel's hardness increases, its resistance to denting and rolling increases, but its likelihood to chip also increases. At the same time, these two characteristics are also greatly affected by edge geometry. So while a steel at one HRC level may have excellent edge stability at 15 degrees, it could be much more stable at 20, with cost to wear resistance and cutting ability; paradoxically, it could also have much more wear resistance and cutting ability at 10 degrees, but the likelihood of the edge remaining stable at such an acute angle is lesser. On the other hand, the same blade could be kept at 15 degrees, and either be made harder to resist denting/rolling with a cost of increased likelihood to chipping and cracking, or be made softer to reduce likelihood of chipping and cracking, but with the cost of decreased resistance to denting/rolling.

The article discusses all that in much more scientific terms, with respect to material engineering. Lots of jargon like "yield stress" and "elastic modulous" but it's conveyed pretty well into layman's concepts if you read it thoroughly.

[Danke]

You can spot a good HRC yourself by how many likes it gets on Instagram. Five hundred plus and it should be serviceable. Less than that and you should bin it; it just won't have enough HRC to satisfy.

[Deadboxhero]

There are many different ways to get the same hardness but not all are equal because the hardness is only measuring the sum of the constituents in the microstructure not the individual components that contribute the most to strength or toughness or the lack thereof.

A great example is work that was done by Santiago in 1979 in the following diagram.

The graph shows different heat treatment conditions with the force required to fracture over the hardness HRC.



Rockwell hardness is essentially like measuring the body weight and while like with humans higher body weight can correlate with higher levels of strength It's pretty obvious that just having extreme bodyweight is not going to make anyone a world-class powerlifter in itself.



If we could measure body composition It would be a more accurate predictor than just body weight alone.

I'm not saying the consumer needs to do exotic testing on their knives to see the microstructure just purchase from reputable brands and don't get so hung up on being plus or minus one HRC difference.

[Enactive]

There are many different ways to get the same hardness but not all are equal because the hardness is only measuring the sum of the constituents in the microstructure not the individual components that contribute the most to strength or toughness or the lack thereof.

A great example is work that was done by Santiago in 1979 in the following diagram.

The graph shows different heat treatment conditions with the force required to fracture over the hardness HRC.



Rockwell hardness is essentially like measuring the body weight and while like with humans higher body weight can correlate with higher levels of strength It's pretty obvious that just having extreme bodyweight is not going to make anyone a world-class powerlifter in itself.



If we could measure body composition It would be a more accurate predictor than just body weight alone.

I'm not saying the consumer needs to do exotic testing on their knives to see the microstructure just purchase from reputable brands and don't get so hung up on being plus or minus one HRC difference.

Thanks, Shawn! The chart is very helpful to illustrate your points. Hopefully people will read and listen to you and Larrin on this issue.

[Erich]

Anyone tested hardness s35vn on new tenacious/persistence/ambitious?

It's likely around 60.