Bluntcut Metalworks Cruforge V Superquenched Slicer Review.

[bodog]

I just figured making a circular cut (like cutting the top out) would put more stress on the edge than just straight piercing/draw cuts.
But, I see you did twist the blade making an hour glass shape in the top - good enough I reckon.

I'm still waiting for someone to cut/scratch/gouge glass.

If you cut the can open right it won't put any lateral stresses on the edge. Pierce, remove, reposition, pierce again, and repeat until the top is cut off.

That test is what did S30V in at 15 dps for me. Another harsh test is wrist chopping at the rim of a beer or soda can. Elmax in my ZT 0560 could not handle it that well. Vanadis 4E and 52100 could. I haven't tried it with anything else.

 

[jpm2]

If you cut the can open right it won't put any lateral stresses on the edge. Pierce, remove, reposition, pierce again, and repeat until the top is cut off.

That test is what did S30V in at 15 dps for me. Another harsh test is wrist chopping at the rim of a beer or soda can. Elmax in my ZT 0560 could not handle it that well. Vanadis 4E and 52100 could. I haven't tried it with anything else.

The method I use is pierce near the rim and rock the blade back and forth while guiding it around the inside of the rim. Makes a fairly smooth cut.

I wasn't joking about the glass...

 

[SBaker34]

Good idea on the wrist chopping. I did that with a deer antler but haven't posted it here yet.

 

[bodog]

The method I use is pierce near the rim and rock the blade back and forth while guiding it around the inside of the rim. Makes a fairly smooth cut.

I wasn't joking about the glass...

Chopping at glass should be easy. Trying to slice it would be kind of pointless. Trying to whittle it, well, I don't know. I'll give it a shot this weekend.

 

[jpm2]

Chopping at glass should be easy. Trying to slice it would be kind of pointless. Trying to whittle it, well, I don't know. I'll give it a shot this weekend.

I was thinking more like making a 1/4 to 1" scratch with the tip.
Forget the rest.

 

[SBaker34]

Sharpened it to 25 degrees inclusive. Takes a nice edge with stropping.

 

[bodog]

Sharpened it to 25 degrees inclusive. Takes a nice edge with stropping.

Any updates? How do you like it compared to other steels?

 

[SBaker34]

I haven't used a ton lately due to school, however I like it quite a bit. Its also more corrosion resistant than I was expecting, granted I kept it oiled but shaving a sweaty arm can corrode 1095 in minutes.





Edit: After posting I pulled it out, I had coated it in oil and stored it in its sheath a couple days ago, it has a splotchy patina now, I thought it was from something inside the sheath or the was stain from the handle, but if 91% alcohol, simple green and brake cleaner won't touch it then it really can't be anything but a patina, trying to decide if I want to force one or go for a polish instead... decisions decisions.

 

[SBaker34]

Went over it with 1000 grit sandpaper and resharpened at 10DPS/20 inclusive.

 

[samuraistuart]

I was going to suggest bar keepers friend for removing the patina, but you nailed it with the wet dry paper! I am finding that 99% of the "corrosion" on carbon knives I sell comes when the knife is put back into the sheath, or kitchen block, without being wiped down well. Hence, any moisture/nastiness gets deposited inside the sheath. NOT good. I'm glad you're getting decent performance from this knife.

 

[SBaker34]

I was going to suggest bar keepers friend for removing the patina, but you nailed it with the wet dry paper! I am finding that 99% of the "corrosion" on carbon knives I sell comes when the knife is put back into the sheath, or kitchen block, without being wiped down well. Hence, any moisture/nastiness gets deposited inside the sheath. NOT good. I'm glad you're getting decent performance from this knife.

I washed the sheath a few hours before I sheathed the knife. It seemed dry but there was probably some moisture inside and oil caused a patina instead of rust. That would be my guess

 

[bodog]

Went over it with 1000 grit sandpaper and resharpened at 10DPS/20 inclusive.

Can't wait to see how it does at 10 dps.

 

[SBaker34]

I cleaned the sheath again with simple green followed by a soak in dish soap, rinsed it out good, let it dry overnight, washed it again with simple green followed by dawn in the morning, rinsed it out for several minutes, let it dry for several hours, then blew it out with an air compressor and let it sit for another hour, meanwhile I wiped the knife down with an oil soaked cloth several times last night, I wiped it down with an oil soaked cloth again and sheathed it. I haven't gotten around to sawing a hickory plank into more manageable pieces yet so I plan to let it sit undisturbed for a couple days to see if it shows up again, while I find some more things to use the knife for. The patina/staining was quite weird. 1095 will get ugly flaking rust around here if kept in humid environments, but doesn't discolor like that. Although it seemed to be somewhat deep as sandpaper and polish only lightened the staining, I still almost have to wonder if it was some kind of concentration of the anti wear and anti corrosion additives in the oil. Strange.

 

[jdm61]

I have used a fair bit of CruForge V and still have close to 200 pounds of bar stock. I am not so sure what "super quenching" would do for that steel other than increase the risk of it cracking in the quench, at least as far as how I understand the term super quenching. .75% Vanadium is gong to ensure that you will have fine grain assuming you HT it right. Dan Farr, one of the smiths who worked with Crucible to develop the steel, has posted picture in the past of him driving a blade tempered to 59RC though nails with no visible damage. If you have aver tried to hand sand that stuff at 60 or 61, you know also know that it is very abrasion resistant at pretty much any usable hardness. The factory specs say that if you austenize at 1525 and temper at 350, you get 62Rc. I tend to do 1500 and 400, which gives around 61 from what I can tell. I have not tried the lower temperature austenizing at say 1475, which gives very high hardness with stuff like 52100, but I plan to. The one guy I know of who tried that said that he got 68Rc a quench and had trouble tempering to below 63 even with a 515F temper regimen!!!!!
It is very good steel and takes a nasty edge, although according to some who know such things, it is probably not the simple or beginners steel that it was intended to be. Sure you can get good results with rudimentary gear, but precise temperature control, etc is required to get the best out of any hypereutectoid steel. It ain't 1075.

 

[SBaker34]

I have used a fair bit of CruForge V and still have close to 200 pounds of bar stock. I am not so sure what "super quenching" would do for that steel other than increase the risk of it cracking in the quench, at least as far as how I understand the term super quenching. .75% Vanadium is gong to ensure that you will have fine grain assuming you HT it right. Dan Farr, one of the smiths who worked with Crucible to develop the steel, has posted picture in the past of him driving a blade tempered to 59RC though nails with no visible damage. If you have aver tried to hand sand that stuff at 60 or 61, you know also know that it is very abrasion resistant at pretty much any usable hardness. The factory specs say that if you austenize at 1525 and temper at 350, you get 62Rc. I tend to do 1500 and 400, which gives around 61 from what I can tell. I have not tried the lower temperature austenizing at say 1475, which gives very high hardness with stuff like 52100, but I plan to. The one guy I know of who tried that said that he got 68Rc a quench and had trouble tempering to below 63 even with a 515F temper regimen!!!!!
It is very good steel and takes a nasty edge, although according to some who know such things, it is probably not the simple or beginners steel that it was intended to be. Sure you can get good results with rudimentary gear, but precise temperature control, etc is required to get the best out of any hypereutectoid steel. It ain't 1075.

I can vouch for it being abrasion resistant, 1000 grit sandpaper barely touched it. As for super quenching bluntcut would have to explain that, but I believe it was done to refine the grain even more.

 

[BluntCut MetalWorks]

Super Quenched topic has been well discussed in BF; HF; CS; Spyderco forums, so no need to rehash that.

As whether this blade micro-cracked during ht? Well, I can't tell for sure because I only looked at it using light-micrograph. Actual light-micrograph of this blade:

Nano-cracks are quite elusive even under SEM & BSED. Results of my suspended ht-track suffered nano-cracks but it took me over 50hrs to correlated what I am seeing at 60nm to crescent chip on high hardness blades.

I don't see any crack at this resolution (smallest details are at 250 nano meter). Obviously there are 2 big visible RA as-quenched. This test blade tempered at 350F, so hardness probably at least 62rc. Also no cryo involve (my dewar is empty and won't fill it for for quench purpose but might do it for extended soak). At this low temper temperature, I expect RA mostly the same amt AQ. This blade designed as a slicer, so if RA end up convert the Mart when impacted, that has been accounted for, treating un-tempered mart as matrix at maximum hardness. It would be great if someone test Phil Wilson Southfork as done in this thread. Nah, my wishful thinking

The twin of this test blade got tempered around 425F ~61-62rc. It's also a slicer except with lower strength and higher toughness.

 

[jdm61]

What is your definition of a super quench ? Most references that I have seen to involve using stuff like a lye solution to quench steels that do not have sufficient carbon to harden to usable levels using normal techniques. The one anecdotal example I have is someone using lye to harden a blade made from something like 1018 to pass the ABS JS performance test. Conventional wisdom says that this is not a good thing with a deep hardening steel like CFV. It is supposedly made to use with petty much any quenchant, but I can tell you from personal experience that while it seems to work fine with fast quenchants like Parks #50 in thicker knife sized cross sections, it can get kind of funny with very thing sections. By funny, i mean I had a small ktichen knife tear itself apart.
According to the Crucible charts, the normal 1525 austenizing with a 350 temper will give you 62Rc, According to the one person I know who tried it, austenizing below the "saturation point" say at 1475 would possibly give you a MUCH harder blade at 350F and 425F.
In the case of Phil Wilson, my impression is that he works with a number of materials that are so highly alloyed that some jokingly say that aren't really steel because they don't have enough iron. CruForgeV has a "lot" of vanadium compared to say some of the other simple carbon/tool steels that have jus enough to primarily control grain growth, but it is still a pretty low alloy steel.

Super Quenched topic has been well discussed in BF; HF; CS; Spyderco forums, so no need to rehash that.

As whether this blade micro-cracked during ht? Well, I can't tell for sure because I only looked at it using light-micrograph. Actual light-micrograph of this blade:

Nano-cracks are quite elusive even under SEM & BSED. Results of my suspended ht-track suffered nano-cracks but it took me over 50hrs to correlated what I am seeing at 60nm to crescent chip on high hardness blades.

I don't see any crack at this resolution (smallest details are at 250 nano meter). Obviously there are 2 big visible RA as-quenched. This test blade tempered at 350F, so hardness probably at least 62rc. Also no cryo involve (my dewar is empty and won't fill it for for quench purpose but might do it for extended soak). At this low temper temperature, I expect RA mostly the same amt AQ. This blade designed as a slicer, so if RA end up convert the Mart when impacted, that has been accounted for, treating un-tempered mart as matrix at maximum hardness. It would be great if someone test Phil Wilson Southfork as done in this thread. Nah, my wishful thinking

The twin of this test blade got tempered around 425F ~61-62rc. It's also a slicer except with lower strength and higher toughness.

 

[samuraistuart]

I wanted to stay away from talking about superquenching CFV in this thread. But since it was brought up.....Luong, this is for you, my friend. If I butcher the thought process, please correct me.

Superquench is indeed basically a brine solution with jet dry added, and maybe dish soap? Forget the exact formula. The idea of superquench was to get low carbon steels to harden decently. And the thought of using what amounts to a BRINE quench on such deep hardening steels such as 52100 and CFV is normally anathema to us knife makers and heat treaters! Heck, Parks 50 alone has shredded some thin CFV blades, JDM was that you? ha ha! So when someone is successfully superquenching CFV and 52100 without the steel coming apart during Ms-Mf, something is going on for sure!

I think we all know that the finer grain a steel has, generally speaking, the lower its hardenability. That is to say, the finer the aus grain a steel has, the faster the quench needs to be. So if CFV is being superquenched successfully, then the steel must to have been cycled so many times, especially in the subcritical ranges, to shrink that aus grain to the point where a brine quench will work. However, aus grain is just half of the steel equation, carbides being the other half, and how THEY are taken care of is probably more important overall than uber small aus grain. IIRC, Luong will not disclose the entire heat treat procedure for his superquenching of 52100 and CFV, and that's fine....it's his right to do so! But in my own understanding, I think that MUCH of the performance that CFV is capable of is being left on the table by superquenching it. Lower hardening temps I am almost certain were used here, and almost certain that the carbon in solution is relatively less than a conventional heat treat, although according to his image above, he is getting above 65 after quench. That is good for sure, nothing wrong with that. I expect 66, maybe 67. I heard the 68 story, and how 515°F tempers were used to bring that down. WOW.

There is alot of hype towards super small aus grain, and there are obviously great advantages to small grain. I myself believe there is a point of diminishing returns with doing all of that cycling just to get the smallest aus grain possible, energy and time spent doing it. What JDM said about the vanadium is spot on when working steels like CFV. There's .75% of the stuff....not like there's just enough for grain pinning, either. There's PLENTY of vanadium for grain pinning, and obviously excess vanadium that shows up as vanadium carbide in CFV images. (not seeing the VC in Luong's image...not sure why....those darker spots on the lower half of the image may be VC).

If I were to try superquenching my CFV, it would look like the Death Star at the end of Return of the Jedi. Kaaabooooom. It IS a deep hardening steel after all! I've done one coupon when I first got the steel, after breaking it and examining the grain structure, it looked like gray velvet. Standard heat treat, canola quench. Carbides taken care of.

Indeed, hand sanding CFV is no walk in the park, and it seems that if you temper it a bit higher, it is a bit easier to hand sand, but who wants a CFV blade any lower than 60-61? Can I get an "amen!" hee hee! Just to share my HT after talking with Adam DesRosiers: normalize HOT, at least 1750°F and air cool. Cycle down, air cool to black between, subcritical as well. 1475°F for 15 minutes, quench 130°F canola. Probably 66 here. At least two tempers, one hour each at 400°F, giving around 62-63, best I can tell. Haven't done sub zero or cryo, probably of no use, RA should be minimal using 1475. There may be advantages besides full RA reduction when going full on cryo, as in matrix/carbide cohesion, eta carbide precip, etc.

 

[BluntCut MetalWorks]

Thanks Jim.

Instead of using Lye solution, SQ (super quench) uses Brine+Dish-Detergent+Surfactant. SQ rates as a 3 seconds quenchant (brine ~5s, p50 ~7s). Quenching crack you mentioned are macro with size from 1mm to the whole blade width. My current SQ ht doesn't suffer any macro nor nano quench cracks.

I almost use the same SQ ht params for most low Cr carbon steels (5160, 1095, 52100, Cfv, Hitachi White & Blue#2, ...). I also selectively SQ mid-Cr (semi stainless) with carbon from 0.6% to 2.5%. If a person just aust/heat and sq dunk, failure rate (due to macro crack) will be over 99%. SQ any steels with carbon in solution > 0.4% is at risk of macro cracks. Discuss for why doing SQ is a long discussion, thus too OT in this thread.

Cfv specifically - I've a whole 0.114" thick sheet (23" x 36") and quite a few 1/4" thick bars. I plan to SQ all my Cfv knives. At this point in time & market space, I think, I am the only one capable of producing SQ knives using steels with carbon over 0.6%. I wish there are more than just me doing SQ, so I can exchange notes :thumbup:

What is your definition of a super quench ? Most references that I have seen to involve using stuff like a lye solution to quench steels that do not have sufficient carbon to harden to usable levels using normal techniques. The one anecdotal example I have is someone using lye to harden a blade made from something like 1018 to pass the ABS JS performance test. Conventional wisdom says that this is not a good thing with a deep hardening steel like CFV. It is supposedly made to use with petty much any quenchant, but I can tell you from personal experience that while it seems to work fine with fast quenchants like Parks #50 in thicker knife sized cross sections, it can get kind of funny with very thing sections. By funny, i mean I had a small ktichen knife tear itself apart.
According to the Crucible charts, the normal 1525 austenizing with a 350 temper will give you 62Rc, According to the one person I know who tried it, austenizing below the "saturation point" say at 1475 would possibly give you a MUCH harder blade at 350F and 425F.
In the case of Phil Wilson, my impression is that he works with a number of materials that are so highly alloyed that some jokingly say that aren't really steel because they don't have enough iron. CruForgeV has a "lot" of vanadium compared to say some of the other simple carbon/tool steels that have jus enough to primarily control grain growth, but it is still a pretty low alloy steel.

 

[BluntCut MetalWorks]

Thanks Stuart - I like your analytical thinking quite a bit.

I've tried many different ht params for Cfv. When SQ cfv, even with carbon in solution is between 0.45% and 0.6% (lower aust temp & short soak); if grain is large, it will cracks probably right around M(80%). To SQ successfully, aust grain boundaries must mostly free of large conglomerated & agglomerated particles, of course fine aust grain implies more gb interfaces. Grain pinning take precedence from particle/carbide first before going down to fine ceramic then to atomic. Take a hard look at Zener Pinning concept and visualize how ocean waves would break up when introduce large & small objects on+near surface.

LOL - I am alone in the SQ world, hopefully I can infect the users with my products

I wanted to stay away from talking about superquenching CFV in this thread. But since it was brought up.....Luong, this is for you, my friend. If I butcher the thought process, please correct me.

Superquench is indeed basically a brine solution with jet dry added, and maybe dish soap? Forget the exact formula. The idea of superquench was to get low carbon steels to harden decently. And the thought of using what amounts to a BRINE quench on such deep hardening steels such as 52100 and CFV is normally anathema to us knife makers and heat treaters! Heck, Parks 50 alone has shredded some thin CFV blades, JDM was that you? ha ha! So when someone is successfully superquenching CFV and 52100 without the steel coming apart during Ms-Mf, something is going on for sure!

I think we all know that the finer grain a steel has, generally speaking, the lower its hardenability. That is to say, the finer the aus grain a steel has, the faster the quench needs to be. So if CFV is being superquenched successfully, then the steel must to have been cycled so many times, especially in the subcritical ranges, to shrink that aus grain to the point where a brine quench will work. However, aus grain is just half of the steel equation, carbides being the other half, and how THEY are taken care of is probably more important overall than uber small aus grain. IIRC, Luong will not disclose the entire heat treat procedure for his superquenching of 52100 and CFV, and that's fine....it's his right to do so! But in my own understanding, I think that MUCH of the performance that CFV is capable of is being left on the table by superquenching it. Lower hardening temps I am almost certain were used here, and almost certain that the carbon in solution is relatively less than a conventional heat treat, although according to his image above, he is getting above 65 after quench. That is good for sure, nothing wrong with that. I expect 66, maybe 67. I heard the 68 story, and how 515°F tempers were used to bring that down. WOW.

There is alot of hype towards super small aus grain, and there are obviously great advantages to small grain. I myself believe there is a point of diminishing returns with doing all of that cycling just to get the smallest aus grain possible, energy and time spent doing it. What JDM said about the vanadium is spot on when working steels like CFV. There's .75% of the stuff....not like there's just enough for grain pinning, either. There's PLENTY of vanadium for grain pinning, and obviously excess vanadium that shows up as vanadium carbide in CFV images. (not seeing the VC in Luong's image...not sure why....those darker spots on the lower half of the image may be VC).

If I were to try superquenching my CFV, it would look like the Death Star at the end of Return of the Jedi. Kaaabooooom. It IS a deep hardening steel after all! I've done one coupon when I first got the steel, after breaking it and examining the grain structure, it looked like gray velvet. Standard heat treat, canola quench. Carbides taken care of.