Steel inquires. 440C vs D2, 5160 vs 10xx, strength vs ease of sharpen

B

bubblewhip

Joined
Dec 18, 2009
Messages
248
I was wondering about a couple of steel questions I wanted answered. One of them was while I was searching the CPM site and looking up D2 and 440C. It shows that 440C and D2 are nearly equivilent of each other in both wear resistance and toughness. Why do manufactures regard 440c as a mid range upper end steel while D2 is regarded as a high end steel? Shouldn't 440C be better because it is a stainless vs a non-stainless? What advantages does D2 have against 440C?

I was also wondering about 5160 or spring steel vs the 10xx series, what advantages does 5160 offer against 1095?

There was something else I hear from custom knife makers that stainless blades are harder to sharpen than non-stainless, but carbon steel blades can hold an edge as well as many stainless. We know that ease of sharpening and strength are inverses of each other, but is there an exception to this rule when comparing stainless to non stainless?

Also why are most cheap knives made out of stainless steel?

That's the 4 questions I wanted answered.
 
bubblewhip said:
I was wondering about a couple of steel questions I wanted answered. One of them was while I was searching the CPM site and looking up D2 and 440C. It shows that 440C and D2 are nearly equivilent of each other in both wear resistance and toughness. Why do manufactures regard 440c as a mid range upper end steel while D2 is regarded as a high end steel? Shouldn't 440C be better because it is a stainless vs a non-stainless? What advantages does D2 have against 440C?

I was also wondering about 5160 or spring steel vs the 10xx series, what advantages does 5160 offer against 1095?

There was something else I hear from custom knife makers that stainless blades are harder to sharpen than non-stainless, but carbon steel blades can hold an edge as well as many stainless. We know that ease of sharpening and strength are inverses of each other, but is there an exception to this rule when comparing stainless to non stainless?

Also why are most cheap knives made out of stainless steel?

That's the 4 questions I wanted answered.
Click to expand...

1) I have never seen 440C equated to D2 in performance on anyone's steel chart. I think you are misinterpreting the information. Those comparison charts on the Crucible web site are specific to each data sheet. Unless both steels appear on the same data sheet and on the same graph, you cannot use those graphs to compare them.

2) 5160 is an alloy steel. 1095 is a carbon steel. (Carbon steels only control the amount of carbon. Alloy steels have controlled amounts of other elements in the formulations). Also, 5160 is not very close in carbon content to 1095. 5160 will make a better chopper because it is tougher. 1095 will make a better slicer.

3) I do not understand your question.

4) Cheap knives are stainless because the average user of low end knives does not want to take care of a non-stainless blade. Low end stainless is not much more expensive than plain carbon steel. The difference in materials cost between the two disappears in the manufacturing costs. This is true for most knives. Materials costs are a tiny fraction of the cost of the knife. It is designing, processing, overhead, advertising, distribution costs that are the main contributors to the cost of the knife.
 
knarfeng said:
1) I have never seen 440C equated to D2 in performance on anyone's steel chart. I think you are misinterpreting the information. Those comparison charts on the Crucible web site are specific to each data sheet. Unless both steels appear on the same data sheet and on the same graph, you cannot use those graphs to compare them.

2) 5160 is an alloy steel. 1095 is a carbon steel. (Carbon steels only control the amount of carbon. Alloy steels have controlled amounts of other elements in the formulations). Also, 5160 is not very close in carbon content to 1095. 5160 will make a better chopper because it is tougher. 1095 will make a better slicer.

3) I do not understand your question.

4) Cheap knives are stainless because the average user of low end knives does not want to take care of a non-stainless blade. Low end stainless is not much more expensive than plain carbon steel. The difference in materials cost between the two disappears in the manufacturing costs. This is true for most knives. Materials costs are a tiny fraction of the cost of the knife. It is designing, processing, overhead, advertising, distribution costs that are the main contributors to the cost of the knife.
Click to expand...

asdxzczxv.png


For the 3rd one, I mean that is there an instance when comparing carbon steel to stainless steels, where a carbon steel blade can hold an edge better than a stainless and at the same time be easier to sharpen than a stainless?
 
Please cite the source of the data sheet. If this is a data sheet for CPM 10V, then I might agree that, compared to CPM 10V, D2 and 440C are roughly the same in abrasion resistance. But if you just comparing D2 and 440C to each other, then D2 is much more abrasion resistant than 440C.


Oh. In that case,
3) if both are hardened to about the same hardness, then 1095 will hold an edge better than AUS 8, though I think there is not much difference between them in ease of sharpening. Does that help?
 
Answers in no particular order:

5160 will be potentially tougher than 1095 for a couple of reasons. It has less carbon, and it is a low alloy steel.

Carbon content and toughness potential are inversely related. As carbon content goes down, toughness generally goes up. 1030 and 1040 carbon steels are very tough, even when compared to 5160, but they don't reach hardnesses that are generally acceptable for knives.

The low alloy steels are a direct upgrade from the 10xx series. The small additions of a few alloy elements allows the steel to have greater potential for toughness and ductility at the same hardness. I say potential because it is dependent on heat treatment. Annealed 1095 (as soft as you can get it) will likely be tougher than fully hardned 5160.

About the best you can do is to compare individual knives of the 2 different steels for your needs, especially if you don't know what the relative hardnesses are or how the maker got there. Of course, the same applies to edge holding, but this favors 1095 instead of 5160.

The comments about sharpenability, edge holding, and stainless vs. carbon are so vague as to be nonsense. At one time, maybe 20 years ago, it could have been a generalization that was true, but not anymore. You need to know the particular alloys in question and have some information about them to make any statements on these properties.

Just as important, if not more so, is the geometry of the knife blade. A thick carbon steel blade will take much longer to sharpen than a thinly ground stainless one.

Also, you need to know the definition of carbon and stainless steel the person you're talking to is using. Some people group steels like CPM 10V, CPM M4, and 1095 all in the same "carbon steel" group, simply because none of them are stainless. However, if you ever try to sharpen the first 2 steels by hand after being used to 1095, you will learn quickly that you are in for some work.

This is getting rather complicated I realize, so here are some short answers. 5160 is tougher than 1095, but doesn't hold its edge as long. 440C won't hold it's edge as long as D2, but D2 will be more time consuming to sharpen, if the blades are ground the same. If you live near salt water, 440C may be a better choice. In the steel comparisons you listed, the thicker blade will take the longest to sharpen, regardless of steel used. Stainless vs. carbon is so vague a comparison, the question can't really be answered.
 
M4 is really easy to sharpen and might even be easier to sharpen than the 10XX steels in my experience. It sharpens very easy compared to how long it holds an edge which doesn't make a whole lot of since.
 
knarfeng said:
If this is a data sheet for CPM 10V, then I might agree that, compared to CPM 10V, D2 and 440C are roughly the same in abrasion resistance. But if you just comparing D2 and 440C to each other, then D2 is much more abrasion resistant than 440C.
Click to expand...

??? Wouldn't the difference between D2 and 440C abrasion resistance still show on the graph regardless of other graph components, i.e. 10V in there?
The height of the bars for 10V and 15V might make D2 and 440C bars look the same height, but I think if it was anything significant then it'd be still noticeable.
May be the graph is wrong in general, but I doubt 10V on the graph is influencing (as in hiding) differences between D2 and 440C.
 
I was giving them the benefit of the doubt I suppose, or maybe the graph shows abrasion resistance as measured by some specific technique. It certainly does not show the difference between the two alloys when they are used as knife blades.
 
knarfeng said:
I was giving them the benefit of the doubt I suppose, or maybe the graph shows abrasion resistance as measured by some specific technique. It certainly does not show the difference between the two alloys when they are used as knife blades.
Click to expand...

The "tool steel comparograph" uses adhesive wear, like for drills, saws, and such. Even so, I'm surprised that they list 440C and D2 as equals.
 
cotdt said:
The "tool steel comparograph" uses adhesive wear, like for drills, saws, and such. Even so, I'm surprised that they list 440C and D2 as equals.
Click to expand...

Thanks. Good to know.
 
I'm looking to buy a kukri made in Indonesia on my next trip over there and there are two knife makers that I'm looking at. One knife maker uses 440C and the other uses D2. For a kukri what would be a better steel?
 
Yes, carbon steels are usually easier to sharpen but not always.

As for wear resistance, it takes a steel like S30V to keep up with a good carbon alloy like 52100, as I like to say.... stainless steels are just starting to catch up to the carbons. It takes using a lot of different steels to fully understand but you get the idea.
 
cotdt said:
The "tool steel comparograph" uses adhesive wear, like for drills, saws, and such. Even so, I'm surprised that they list 440C and D2 as equals.
Click to expand...

Yeah, there can be big differences between wear resistance to adhesion versus wear resistance to abrasion. Look at the comparison chart towards the end of the following between D2 and some other tool steels:
http://www.bucorp.com/files/aisi_d2.pdf

So before you apply wear resistance charts or comparisons in regards to knife performance, you have to make sure it is the applicable measure of wear resistance? hummmm....:confused:
 
Adhesive wear is more common. We ignore it, fatigue, and fretting, but I don't know why, or how pronounced any of these are on a ~0.5-1 micron cutting edge. I think the important thing is not to look at wear resistance in a vacuum, but to also consider toughness, strength (hardness), corrosion resistance, edge finish & geometry, environment of use, cutting method, and cut material.
 
skyahn83 said:
I'm looking to buy a kukri made in Indonesia on my next trip over there and there are two knife makers that I'm looking at. One knife maker uses 440C and the other uses D2. For a kukri what would be a better steel?
Click to expand...

440c


10 places
 
hardheart said:
Adhesive wear is more common. We ignore it, fatigue, and fretting, but I don't know why, or how pronounced any of these are on a ~0.5-1 micron cutting edge. I think the important thing is not to look at wear resistance in a vacuum, but to also consider toughness, strength (hardness), corrosion resistance, edge finish & geometry, environment of use, cutting method, and cut material.
Click to expand...

But if hardness were equal, and if adhesive wear resistance was important in keeping an edge, than an edge retention comparison between 440C and D2 would be closer than it is. I think what that info is telling us is that abrasive wear resistance is the critical type of wear resistance that we want for high edge retention, and adhesive wear resistance is not nearly as important. For instance O1 has much higher adhesive wear resistance than D2 (at low sliding speeds that would be comparable to hand cutting), but we all know that D2 is more wear resistant in sharpening and edge retention than O1.

http://www.sciencedirect.com/scienc...serid=10&md5=a085ef7da62816f19a9eb187c0942d62
 
we know it is more wear resistant in sharpening, but edge retention depends on what & how we are cutting and measuring. Edge retention is really poorly defined. Everything has the same edge retention if it's stored in a time capsule, once we start using the knives we get different results depending on what we do.

I don't even know how far apart 440C & D2 are in edge retention, and under what circumstances this was measured. Is it the same difference across a range of hardnesses, edge finishes, angles, and for all materials & types of cutting?
 
You must log in or register to reply here.
Back
Top