How good is Emerson's 154cm and some other questions?

[Jason B.]

The couple points of hardness from 60 to 57 provides exactly ZERO improvement in terms of ease of sharpening. Wear resistance plays much, MUCH bigger role in sharpening than hardness. In other words, 154 at 61 will be the same as 154 at 57 in practice.

That is not true at all.

Factors of wear resistance are for high vanadium steels of which 154cm is not. 154cm at Rc57 is similar to AUS-8 in performance and not much different in sharpening. 154cm at Rc61 is more like ZDP (@Rc65+) with sharpening and performance, 154cm at that hardness has amazing edge stability that would allow 20 degree inclusive angles and not even sweat it.

A few points of hardness makes a world of difference.

 

[CrimsonTideShooter]

Well of course hardness affects edge retention, who said it didn't? Hardness does affect how a steel performs, but when it comes to putting steel to stone, 3 points of hardness (same alloy) is not going to make the hard blade laborious to sharpen, and the soft blade "easy."

It just doesn't work that way. The actual hardness of a material doesn't matter much at all when you are talking about material removal (sharpening). Look at Ti, at around 40hrc it is one of the hardest materials to grind and work with.

Also, what are you talking about when you say wear resistance doesn't apply to 154cm? How could a trait of steel just not apply to 154cm? Hell, even crucible says that 154cm has good wear resistance. Vanadium is not needed for a steel to have wear resistance, just carbides.


ETA: you'd think if hardness played a huge role in sharpening (abrasion) then crucible would do their pin abrasion test (wear resistance test) at a range of hardnesses.....

That is not true at all.

Factors of wear resistance are for high vanadium steels of which 154cm is not. 154cm at Rc57 is similar to AUS-8 in performance and not much different in sharpening. 154cm at Rc61 is more like ZDP (@Rc65+) with sharpening and performance, 154cm at that hardness has amazing edge stability that would allow 20 degree inclusive angles and not even sweat it.

A few points of hardness makes a world of difference.

 

[Jason B.]

Hardness will have a direct impact on the sharpening ability of 154cm or any other steel. Who ever told you it didn't told you wrong. Higher hardness adds resistance to deformation and fracture thus making the steel harder to grind. I sharpen 154cm and CPM-154 way more than I would like to and most of it is in high end kitchen cutlery that has been professionally hardened to 61-62, there is a HUGE difference in sharpening ability from those at high hardness to a Emerson at 57 which grinds like soft butter.

Everything has wear resistance but with cutlery steels if you start speaking wear resistance everyone will compare it with wear resistance like you see in S30V. This is bad because is causes confusion. 154cm has good wear resistance but it is not a high vanadium type wear resistance as each is completely different in edge performance and breakdown. Changing wording and describing 154cm to have long lasting sharpness or excellent edge retention keep the traits of edge performance in line with the description. Saying it has good wear resistance make it sound like a high wear steel where the edge performance is nothing alike.

 

[CrimsonTideShooter]

Knifeknut, sharpening is neither deformation or fracturing, it is simply material removal. It is a sped up form of wear, plain and simple.

2 or 3 points in hardness does not affect wear resistance enough to make one knife noticeably harder or more time consuming to sharpen. I'm not disputing that you can feel a difference, because I can on my own stones. I am disputing the idea that 154cm at 57 will be "quick and easy" to sharpen, while 154cm at 60 will be laborious and time consuming, given the sharpening materials stay constant.

If that was the case, crucible would perform their pin abrasion test at a range or hardnesses and post the data. Know why they don't? Because the difference in neglible.

I love how people use ZDP-189 as a benchmark for "hard to sharpen" citing its high hardness. The reason ZDP is hard to sharpen is because it has copious amounts of carbides.


I guess we will just have to agree to disagree.

 

[The Mastiff]

If that was the case, crucible would perform their pin abrasion test at a range or hardnesses and post the data. Know why they don't? Because the difference in neglible.

They don't post the hardness in all cases but they do use the best heat and temper ( = final hardness) for the abrasion number, toughness numbers, or best corrosion performance. It's important they do this especially in steels that have a double tempering curve like 154cm/cpm154/ats34. It's almost like two different steels. Naturally they give the best heat treat instructions to achieve either depending on your goal.

2 or 3 points in hardness does not affect wear resistance enough to make one knife noticeably harder or more time consuming to sharpen

Notice any difference in 1095 or O-1 at 57 then again on a custom at rc 64-65? I do. Not much carbides in either.

Joe

 

[CrimsonTideShooter]

Hey Mastiff, sure you can feel a difference on the stones. But, the difference between the two isn't enough to make much of a difference in time spent sharpening, or difficulty in attaining a keen edge.

That's my whole point. Sure, there is a bit of difference when there is a disparity in hardness. Is 3 points of hardness enough to justify running the steel soft for "ease of field sharpening?"

Absolutely not.




Now, the difference between through hardened steel, and that same steel in its annealed state probably does make that much of a difference.

 

[The Mastiff]

Hey Mastiff, sure you can feel a difference on the stones. But, the difference between the two isn't enough to make much of a difference in time spent sharpening, or difficulty in attaining a keen edge.

That's my whole point. Sure, there is a bit of difference when there is a disparity in hardness. Is 3 points of hardness enough to justify running the steel soft for "ease of field sharpening?"

Absolutely not.

If you treat the CPM 154 for maximum corrosion resistance and it's at Rc 57, you will notice a huge difference while sharpening and in using wear resistance compared to a CPM 154 blade tempered for maximum wear resistance running at rc 61. It's like completely different steels. Of course it's more than just a hardness difference involved here. The structure is different.

Joe

 

[hardheart]

Pin on disk is an adhesive wear test, not abrasive. Referencing abrasive wear tests is likely preferable for how we use and dull knives. Wear tests are done at different hardnesses, but it is true most of the advertised graphs don't show differences.

The rockwell scale is roughly logarithmic, kind of a different animal. The decibel scale actually is logarithmic, and a 3 point increase on the scale means the sound is twice as loud. Much in the same way we think a difference of 70 to 73 decibels isn't much, and sound isn't loud until you get quite a bit higher, the perception of time and effort to sharpen between 57 and 60 rockwell isn't either. It is based on gross body movement in sharpening where we do things like grind away to fix chips, lower bevel angles, and restore edges. The grinding is of a very small and fragile section of steel often being abraded by dedicated sharpening equipment with abrasive particles many times harder than the martensite of the blade. The difference is definitely there for grinding operations, strength of the steel, edge holding, etc, but perhaps when you collect knives of many different alloys, geometries, designs, uses - and sharpen them with a variety of equipment, such a level of difference is washed out in experience. Going back to precise measurements, we know the difference does exist and to what degree. Sharpening on less than optimal equipment, or in less than optimal conditions, those 3 points likely have a noticeable effect. I don't particularly care for the softer steels, as they respond poorly on the stones. They are easy to abrade, but that doesn't necessarily mean they give great edges. Lowering hardness reduces wear resistance, but that has to be balanced. We want/need both grindability and wear resistance, so improvements like PM provide that.

Here's a short paper from the steel monster that is now Carpenter/Latrobe/Crucible
www.latrobesteel.com/assets/documents/datasheets/Bulletin_116.pdf

ZDP-189 has lots of chromium carbide, which is much closer to cementite than the other carbides formed, and far below the hardness of vanadium carbide.
Sharpening can and does involve deformation and fracture along with abrasion. It depends on the steel, the stones, and the sharpening technique. Edges are often burnished as part of sharpening, and fractures occur, though we don't want them to. Unless we're dealing with obsidian blades, then we get much, much sharper edges from that.

 

[snowreaper1]

Emerson 154cm is good steel. Sure theres other companies like Spyderco coming out with all these exotic super steels but for an average knife user I don't think that should be a deciding
factor on whether you buy the knife or not. Emersons 154cm is incredibly corrosion resistant which I think is a great trait in a user steel. And if you maintain your knives by routinely stropping
and honing your knife that edge will be good to go everyday all day.

As far as how good Emerson knives are out the box I will have to say they do a poor job of the finishing touches when it leaves the factory. The action will be gritty and the lock bar is usually really
rough cut resulting in a sticky lock. But once I took my horseman apart, cleaned it up, sanded the lock bar smooth, and broke it in it performed 100 times better. I love Emerson blades with the nice
stone wash/ satin finish and sweet grinds but the rest of the knife leaves a lot to be desired.

 

[CrimsonTideShooter]

Hey HH, good info. I am aware that the HRC scale is logarithmic.

In the first sentence you say that the "pin on disc" doesn't measure wear resistance. I don't know what test you are referring to, but I am referring to Crucibles "pin abrasion test", which definitely does measure wear resistance per their own PDF's.

You make a good point. Perhaps I just can't tell a difference, I am but one person after all. Maybe it's the media I use to sharpen?

Pin on disk is an adhesive wear test, not abrasive. Referencing abrasive wear tests is likely
preferable for how we use and dull knives. Wear tests are done at different hardnesses, but it is true most of the advertised graphs don't show differences.

The rockwell scale is roughly logarithmic, kind of a different animal. The decibel scale actually is logarithmic, and a 3 point increase on the scale means the sound is twice as loud. Much in the same way we think a difference of 70 to 73 decibels isn't much, and sound isn't loud until you get quite a bit higher, the perception of time and effort to sharpen between 57 and 60 rockwell isn't either. It is based on gross body movement in sharpening where we do things like grind away to fix chips, lower bevel angles, and restore edges. The grinding is of a very small and fragile section of steel often being abraded by dedicated sharpening equipment with abrasive particles many times harder than the martensite of the blade. The difference is definitely there for grinding operations, strength of the steel, edge holding, etc, but perhaps when you collect knives of many different alloys, geometries, designs, uses - and sharpen them with a variety of equipment, such a level of difference is washed out in experience. Going back to precise measurements, we know the difference does exist and to what degree. Sharpening on less than optimal equipment, or in less than optimal conditions, those 3 points likely have a noticeable effect. I don't particularly care for the softer steels, as they respond poorly on the stones. They are easy to abrade, but that doesn't necessarily mean they give great edges. Lowering hardness reduces wear resistance, but that has to be balanced. We want/need both grindability and wear resistance, so improvements like PM provide that.

Here's a short paper from the steel monster that is now Carpenter/Latrobe/Crucible
www.latrobesteel.com/assets/documents/datasheets/Bulletin_116.pdf

ZDP-189 has lots of chromium carbide, which is much closer to cementite than the other carbides formed, and far below the hardness of vanadium carbide.
Sharpening can and does involve deformation and fracture along with abrasion. It depends on the steel, the stones, and the sharpening technique. Edges are often burnished as part of sharpening, and fractures occur, though we don't want them to. Unless we're dealing with obsidian blades, then we get much, much sharper edges from that.

 

[hardheart]

In the first sentence you say that the "pin on disc" doesn't measure wear resistance.

I said it measures adhesive wear, and steels are tested for adhesive and abrasive wear. Adhesive is for metal parts moving in contact with each other, so good for things like ball bearings, bushings, guide rods, and the like. Abrasive wear is for things like blades and dies cutting papers and plastics. Both are useful measures for tool steels, but abrasion resistance is more relevant for sporting knives.

Sharpening on diamond and ceramic, it doesn't take long. With stones maintained to be completely flat with fresh surfaces, we're talking a couple minutes difference, if that, for high and low carbide/hardness/alloy steels. Rubbing against a river stone or cinder block in the middle of nowhere, probably going to wish the steel wasn't as hard to sharpen as even the softest 154CM. Bringing a sharpener or a spare blade might be a better idea.

 

[snowreaper1]

Emerson stated that with the softer steel coupled with the one sided chisel grind edge you could get a working edge out in the field with a cinder block.
Could definitely be a life saver when your in the shit and your life depends on a usable edge.