Two 1095 questions for experts

[jdm61]

Try austenizing it at a lower temp. The trick is to not allow more than that magic 80% or so to get into solution.

I disagree with you about 1095. 1095 makes cemetite carbides that are large and uneven compared to chromium or vanadium carbides. If it produced a very fine grain it would be a very tough steel, but it does not and is not. 1080, which doesn't have enough extra carbon to produce cemetite is a finer grained steel.

 

[jdm61]

Actually, 80CrV2 fits into the formula range for L2 and it also contains up to .35% silicon along with the .60% C and .25% V, which is yet another alloying element that can "impart " toughness.

Saying 80CrV2 is "just 1080 with a dash" completely misses how powerful alloying is. 80CrV2 is most closely compared to 5160 and L6, two of the toughest steels available. The fact that 3V produces high toughness through rich alloying doesn't mean that low alloys don't also produce very tough, useful knives.

 

[LukeTheSpook]

Now I'm not an expert. Not even close, but I have a ton of knives. From mora to busse to custom.

1095? Well I just used a Tops BOB all day today working wood and building fires. I paid around $85 for it. Now my non expert opinion is it's an awesome knife. 1095 bit deep, made great feathersticks and it's still sharp.

So buy the knife you like, use it. I have s90v, 10v, 3v, infi, sr101, and a bunch others. They are all fun.

Oh and one steel that seems to get crazy sharp super easy? 1085 from the kabar camp knife.

 

[RX-79G]

Try austenizing it at a lower temp. The trick is to not allow more than that magic 80% or so to get into solution.

You mean turn it into 1080 by not allowing all the carbon to get into solution. What happens to the extra carbon? Pockets of pealite, or something else? And what does that extra stuff do the final product compared to 1080?


Thanks for the info on Hitachi. The references to purity and sand iron were confusing.



And you are entirely correct about L2. I simply meant that 80CrV2 is most often compared to the common steels L6 and 5160. 50100b is most comparable to W7, but I've never seen L2 or W7 to have anything to say about them.

 

[jdm61]

50-100B/1095CroVan is the old Sharon 0170-6 recipe. The 50-100B designation is the "generic" AISI name. I do believe that is aslo has a bit of nickel, which W7 does not appear to have. L6 has like 1.5% nickel. 5160 and 80CrV2/Bestar 1.2235/L2 have none. Some variants of L6 like Crucible Champaloy also have a good little dose of Moly which is what makes them a bit tricky about air hardening when coming down from forging temps.

You mean turn it into 1080 by not allowing all the carbon to get into solution. What happens to the extra carbon? Pockets of pealite, or something else? And what does that extra stuff do the final product compared to 1080?


Thanks for the info on Hitachi. The references to purity and sand iron were confusing.



And you are entirely correct about L2. I simply meant that 80CrV2 is most often compared to the common steels L6 and 5160. 50100b is most comparable to W7, but I've never seen L2 or W7 to have anything to say about them.

 

[RX-79G]

50-100B/1095CroVan is the old Sharon 0170-6 recipe. The 50-100B designation is the "generic" AISI name. I do believe that is aslo has a bit of nickel, which W7 does not appear to have. L6 has like 1.5% nickel. 5160 and 80CrV2/Bestar 1.2235/L2 have none. Some variants of L6 like Crucible Champaloy also have a good little dose of Moly which is what makes them a bit tricky about air hardening when coming down from forging temps.

I believe the nickel went away in the later incarnations of 50100B from the original Sharon steel.

 

[me2]

I disagree with you about 1095. 1095 makes cemetite carbides that are large and uneven compared to chromium or vanadium carbides. If it produced a very fine grain it would be a very tough steel, but it does not and is not. 1080, which doesn't have enough extra carbon to produce cemetite is a finer grained steel.

There also seems to be a little confusion about cementite. Fe3C (cementite) can be extremely small, smaller than typical VC. With only about 2 to 3 percent volume of carbides, 1095 certainly doesn't have large or uneven carbides. Grain size and carbide size are not the same. Grain size of 1095 with a good heat treatment will be on par with other low alloy steels mentioned, including 1080, ASTM 8 to 10. CPM processing is about controlling carbides. Carbides in simpler steels are controllable with heat treatment, so there is no benefit to CPM processing for them.

 

[RX-79G]

There also seems to be a little confusion about cementite. Fe3C (cementite) can be extremely small, smaller than typical VC. With only about 2 to 3 percent volume of carbides, 1095 certainly doesn't have large or uneven carbides. Grain size and carbide size are not the same. Grain size of 1095 with a good heat treatment will be on par with other low alloy steels mentioned, including 1080, ASTM 8 to 10. CPM processing is about controlling carbides. Carbides in simpler steels are controllable with heat treatment, so there is no benefit to CPM processing for them.

Do you think the AISI descriptions of 1095 as "brittle" are accurate or not? If it is accurate, why do you think that is, and does that make 1070 brittle as well?

 

[me2]

Do you think the AISI descriptions of 1095 as "brittle" are accurate or not? If it is accurate, why do you think that is, and does that make 1070 brittle as well?

I would have to read them. Do you have links or references? Brittle and tough are relative so I'd have to see the context of the comparison.

 

[RX-79G]

I would have to read them. Do you have links or references? Brittle and tough are relative so I'd have to see the context of the comparison.

http://www.azom.com/article.aspx?ArticleID=6561
http://www.suppliersonline.com/propertypages/1095.asp

They are just descriptions, rather than impact strength charts (which don't seem to exist for 1095).

Contrast with the "good toughness" of A2:
http://www.hudsontoolsteel.com/technical-data/steelA2


I don't think any of that is definitive. It just reflects the sort of things I've read elsewhere - especially chatting with people like Kevin Cashen. 2-3% carbide volume doesn't sound like much, but we are talking about a type of steel that is 98.5% iron, so when you say the carbide volume is only 2 or 3%, I see the carbides doubling the alloying ingredients volume and wonder if 3% is actually a small number for a steel that doesn't have a ton of chrome or anything else in it.


One damn temper/impact strength chart for 1095 (and the 10xx series) and this wouldn't be a discussion anymore. I just have this honestly obtained idea that cemetite carbides in an otherwise un-alloyed steel matrix hurt impact resistance, while something like 1070 is preferred for train tracks and chrome steels like 52100 for bearings - because both need to be tough.

http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=753&p=6334&hilit=1095+toughness#p6334

http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=230&p=1957&hilit=1095+toughness#p1957

 

[me2]

Interesting links. Doing this on my phone is tedious. Will write more when I'm done traveling.

 

[RX-79G]

Reading more, the issue with cemetite in hypereutectoid steels is how it gets into grain boundaries when the steel starts forming plate martensite. That's what decreases the toughness, and what some alloying elements help to prevent.

 

[me2]

http://www.azom.com/article.aspx?ArticleID=6561
http://www.suppliersonline.com/propertypages/1095.asp

In the context of these links, I'd say they are comparing 1095 to other steels in a general way. In that sense, I'd agree that 1095 is brittle, because that means you could be comparing it to structural steels, medium carbon high strength steels like 4140, 4340, etc, and other wide ranging steels. It also appears these links are steel suppliers/re-sellers/distributors, so I don't know if I'd characterize them as AISI descriptions in a reference material like sense. Along those lines and in that context, I'd call 1070 brittle as well, though less so than 1095.


These links have some issues that I can't tell if they are typos or genuine errors. No one I know of hardens 1095 from 1650 F for knives, which is what we're talking about after all. Also, heating 1095 to 1650 and slow cooling in the furnace is potentially going to cause problems, and will definately lead to brittle 1095 if not corrected later.

They are just descriptions, rather than impact strength charts (which don't seem to exist for 1095).

Contrast with the "good toughness" of A2:
http://www.hudsontoolsteel.com/technical-data/steelA2

Again, in the context of the discussion, I'd agree that A2 has good toughness, but it isn't being compared to 1095 in that link. Based on the other steels listed in the chart, they are comparing it to other cold work die steels. In that sense it has good toughness, less than O1, A8, S7, but better than D2 and M2. Now, I think there is a good chance that 1095 is not as tough as A2, but the difference isn't so great that I'd call one brittle and the other tough. A2 has some things going for it, such as the alloying elements, the air cooling (which helps), and the higher tempering temperature for the same hardness. However, it has considerably more carbide volume (5-6 percent). Again, I'd say A2 is tougher, but not by much, and not by enough to say it is tough and 1095 is brittle. Oh, and I still have some issues about using those types of charts as anything more than a rough guide. This link also appears to be a distributor/supplier of tool steels.


I don't think any of that is definitive. It just reflects the sort of things I've read elsewhere - especially chatting with people like Kevin Cashen. 2-3% carbide volume doesn't sound like much, but we are talking about a type of steel that is 98.5% iron, so when you say the carbide volume is only 2 or 3%, I see the carbides doubling the alloying ingredients volume and wonder if 3% is actually a small number for a steel that doesn't have a ton of chrome or anything else in it.

Alloying element percentages are in weight percent, carbide amounts are typically in volume percent. It's tricky, but you can't really compare the percentages to each other.


One damn temper/impact strength chart for 1095 (and the 10xx series) and this wouldn't be a discussion anymore. I just have this honestly obtained idea that cemetite carbides in an otherwise un-alloyed steel matrix hurt impact resistance, while something like 1070 is preferred for train tracks and chrome steels like 52100 for bearings - because both need to be tough.

Absolutely. I have only seen one temper/impact strength chart for 1095, and it is torsional impact, and cannot be compared to other charts which are usually done in Charpy C-notch or un-notched Charpy testing. That chart also does not have a scale on the vertical axis, and is only for relative comparison for determining the TME region in 1095 (which is quite dramatic). It is also correct that increasing carbide volume lowers toughness. This goes for any carbide, not just cementite, and is a general trend only. Specific steels and HT procedures will vary that A LOT. Cementite has one advantage over other carbide types. It is relatively much easier to shrink, remove, and rearrange cementite for your advantage than it is the others, though Chromium Carbide can be close (reference the Sandvic steels and the extremely small chromium carbides). For instance, just adding more carbon to get more cementite (1.25% C or a little more) can help make steels that are superplastic (greater than 1000% ductility). Only one company I've heard of uses such a steel in such a condition for knives, and when hardened they certainly don't have that property, and the company may have stopped, but the possibility is there.

http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=753&p=6334&hilit=1095+toughness#p6334

http://www.hypefreeblades.com/forum/viewtopic.php?f=3&t=230&p=1957&hilit=1095+toughness#p1957

See above in blue for specific comments on the links and such. As for the hypefree links, I'd have to agree with Kevin that 1095 isn't the steel I'd want for a large chopper or rough use knife, and in that sense, compared to all the other possible steels to pick from for that purpose, I'd say yes, 1095 CAN BE brittle. However, if 1095 is much easier to get in the stock thickness I want, or something like that, it can be heat treated to be very tough while providing adequate edge holding.

I've said on these boards before, from a user perspective, I don't know that there is a huge difference in well done 1095 and well done 52100. Is there a difference? Absolutely. Will it be night and day? No. Will it be to the point that if a knife has features I like, but is in 1095 instead of 52100, I wouldn't buy it? No. From a maker perspective, I'd choose 52100 almost every time. The exception is if I were forging. 52100 is a little more persnickety, and takes more forging skill. If a maker has the skill to handle it, 52100.

It's a little odd, and most likely related just to semantics, but I actually agree with most of what you've said. 1095 can be brittle, and certain heat treatments can make it much worse. Again, I wouldn't call it brittle then call basically any other 1% steel tough (such as 52100, A2, etc.). 1095 is certainly tougher than the common CPM steels, such as S30V, S35VN, M390, CTS-XHP, CPM D2, CPM 154, and some others. With all the short comings of 1095 and the lack of alloying, it's hard for those other steels to overcome carbide volumes in the 10-15% range.

The second link to hypefree is basically my reply to the top posts questions. You are one of the few I've seen here bring up the notions that hardness is not directly related to toughness and carbon content, not tempering temperature, is the correct tool to use when achieving the desired toughness, assuming a variety of steels are available to use. If all you have for a 12" blade chopper is D2, then that's what you'll have to use, but it's an even bigger compromise than 1095.

 

[me2]

Reading more, the issue with cemetite in hypereutectoid steels is how it gets into grain boundaries when the steel starts forming plate martensite. That's what decreases the toughness, and what some alloying elements help to prevent.

Man, I wish I'd read this before typing that wall of text above. Cementite doesn't necessarily form in the grain boundaries, and if it does, you can move it. Plate martensite is a whole other issue.

Here, a little light reading for your carbide forming discussions. It was locked due to Tai's antics, but if you ignore that part, it's relatively straight forward.

http://knifedogs.com/showthread.php?28993-Grains-Carbides-and-You&highlight=grains+carbides

 

[RX-79G]

Man, I wish I'd read this before typing that wall of text above. Cementite doesn't necessarily form in the grain boundaries, and if it does, you can move it. Plate martensite is a whole other issue.

Here, a little light reading for your carbide forming discussions. It was locked due to Tai's antics, but if you ignore that part, it's relatively straight forward.

http://knifedogs.com/showthread.php?28993-Grains-Carbides-and-You&highlight=grains+carbides

Well, I found it all interesting. Thanks!

 

[farmer ted]

Care to explain what is the material designed for each application when it come to knife steel?

Oooohhhh, aaaahhhhh, pretty picture....

What the heck do these morons know about steel?

"The utility of a knife depends on optimizing all the factors affecting its performance. Usually, conditions of use (applied loads, abrasive environments, impacts, and other factors) determine how well the knife holds up. Most knife failures are related to such mechanical causes. However, with a variety of steels available for manufacturing knives, it is often possible to choose a knife steel with a favorable combination of properties for particular uses. By comparing the levels of metallurgical properties offered by different steels, knifemakers can determine which steels are best suited for fixing or resisting performance problems, or for enhancing knife performance. Knife steels can be categorized and compared by those properties which have a direct influence on performance: hardness, toughness (impact resistance), wear resistance, and corrosion resistance."

https://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

 

[Marine E7]

Wow in that chart S30V is amazing. Less chippy then 3v with much more rentention and resistant to rust.

 

[RX-79G]

Oooohhhh, aaaahhhhh, pretty picture....

What the heck do these morons know about steel?


https://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

I don't think you two are actually disagreeing. Choosing an appropriate steel is important, but there are multiple, overlapping steels for every knife type. But there are steels that are not appropriate for some types of knives. You shouldn't try to "fix" a steel by tempering it into something it shouldn't be.

 

[shqxk]

Oooohhhh, aaaahhhhh, pretty picture....

What the heck do these morons know about steel?


https://www.crucible.com/pdfs/SelectorKnifePocketRotatedCrucibleLLC.pdf

And what Crucible selection commercial sheet have anything to do with your Civic to sport car logic?
What steel in your mind that is an inborn sport car and which is Civic?

I'll tell you , each steel type does have their own advantage... Metallurgy properties always came at a trade off...

I have tried using and testing 5160 against 1084 against CPM-3V ... and they all hold an excellent edge pretty much the same because my friend who make those carbon knives do have proper equipment and knowledge. If done right way, they are much closer in performance than you might think...

But I don't blame you since I understand that newer steel always have a wow factor that catch most newbie eye.

This is some good example of steel blind test showing how close of some cheap plain steel perform against to the high tech expensive one when all are done with proper method.

http://www.bladeforums.com/forums/showthread.php/1104795-Steel-testing-underway

 

[RX-79G]

This is some good example of steel blind test showing how close of some cheap plain steel perform against to the high tech expensive one when all are done with proper method.

http://www.bladeforums.com/forums/showthread.php/1104795-Steel-testing-underway

I would not say his 3V heat treat was exactly doing right by the alloy. I think the stuff Aaron does is pretty cool, but a real test involves expert heat treatment of all the samples. I think his results are more about what heat treatments he selected than much about the steels.