Question regarding blade rockwell hardness

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vg10blade

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If a blade made of VG10 has a hardness of 58 and a blade of S30V also has a 58. Would they have the same or similar edge retention? Also what stops the manufacturer to heat treat to a higher hardness? Just looking to increase my knowledge regarding this. I am wondering if its worth buying a more expensive steel if its heat treated to the same hardness of a cheaper steel.
 
Nope. There are other characteristics like; carbide size, grain structure, steel composition and blade geometry that influence edge retention as well...
 
S30V has lots of Vanadium which produces lots of hard wear resistant carbides which also makes it difficult to get a good polish !! Stone finish is OK for me.
 
As already said, there are other factors in steel that affect wear resistance. Rockwell hardness is somewhat a measure of strength, but doesn't give any indication of toughness. Also I'm wondering if the increased carbides in some steels affect the RC testing.

There is always a tradeoff in steel between hardness and toughness. At least some steels can be hardened higher than their range of use in normal knives, but they become too brittle for reasonable use. This is somewhat of an explanation for why knife steels are hardened to different levels, and why they aren't hardened more than they are.

The more I read the more I find that steel composition and steel performance is very complicated.
 
Everyone is getting it right, start reading and just because they have the same HC does not mean they are comparable. Aus-8 at 58 rc does not even compare to N690 at 58rc.
 
If the steel is treated to maximize its specific characteristics, VG-10 will give a very sharp, very fine edge. I've read that VG-10 will make an excellent straight razor. S30V on the other hand will give a relatively rough, carbide infused edge. The edge will last a long time butchering game or cutting cardboard. S30V will be the more durable edge with everything else being equal. However, S30V would be more likely to grab and pull out your whiskers as a straight razor.
 
Rockwell hardness is determined by the resistance of the crystal matrix to penetration by a weighted diamond pyramid. Putting hard materials (carbides) into the matrix does not affect the resistance to penetration but can affect the wear resistance of the blade (like putting hard stones in cement). So you could say that Rockwell hardness contributes to edge life and so do inclusions. A 58 HRC blade would be improved by the inclusion of some Vanadium carbides at 82 HRC.
 
Something to consider, rust scale has a really high Rockwell hardness. But it don't make a good blade steel, food for thought.
 
vg10blade said:
If a blade made of VG10 has a hardness of 58 and a blade of S30V also has a 58. Would they have the same or similar edge retention? Also what stops the manufacturer to heat treat to a higher hardness? Just looking to increase my knowledge regarding this. I am wondering if its worth buying a more expensive steel if its heat treated to the same hardness of a cheaper steel.
Click to expand...

If everything was exactly the same as in 2 exact knives except for the steel then S30V would have better wear resistance than VG-10 due to the higher carbide content.

The difference would show up more on abrasive media so the perception may vary depending on actual use.

It's not just the hardness that matters however.

But hardness does factor into the overall edge stability and strength of the edge, the reason why S30V at 61 would hold an edge longer than S30V at 58 for example.

Or the difference between 1095 at the normal 56-58 compared to 64 as another example.

But in the end it's all a trade off so everything has to be considered in the end knife, how it's going to be used etc.

For harder use like choppers a lower hardness, lower alloy steel would be used over a higher hardness high alloy steel.

The reason why something like A2 would be a better choice for a large blade in a chopper than something like S30V all things being equal.

There are a lot of variables and steels that are designed for various tasks and some are more suited to certain things than others are.

Worth will vary depending on opinions and a persons budget etc.

The higher alloy steels cost more for a reason, higher alloy content costs money and so does different technologies.

Most of the steels that are used in knives have been adopted from other parts of the steel industry and adapted for knife use, and that's almost all of them except for a very small handful.
 
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