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CPM-15V Folder...?
- Thread starter dwl4653
- Start date
- Joined
- May 26, 2000
- Messages
- 1,922
I don't know of anyone using 15V routinely for anything. Phil Wilson has made blades from it and tested it, but he chooses 10V if you want his "ultimate slicing blade". I suspect he didn't find enough additional edge holding for the hardness he had to bring 15V down to to keep toughness at equivalent levels w/ 10V.
Crucible's literature says that CPM 15V has 50% better wear resistance than does their 10V.
And they claim 10V to be 4 times better than D2.
Of course, what you give up is toughness at a given level of hardness. From a chart on page 35 of the "Crucible Tool Steel & Specialty Alloy Selector" book:
Steel.............Charpy C ft-lb....relative wear resistance
===============================================
CPM15V..@Rc60.........10..................15
CPM10V..@Rc60.........20..................10
CPM3V...@Rc58.........85...................2.8
M2..........@Rc62.........20...................3
D2..........@Rc60.........20...................2
A2..........@Rc60.........40...................1.3
S7..........@Rc56........120...................0.5
(just in case, Charpy C notch test involves milling out a C shaped notch in a bar of steel, and measuring the sudden, impact force required to snap the piece, often with a swinging weight... a toughness test.)
S7 is used for jackhammer bits, for example.
So 15V is 1/2 as tough as 10V for (claimed) 50% increase in slicing/abrasion/wear resistance.
What I'd like to see is a chart showing how much 15V's wear resistance deteriorates when it is brouht down in hardness enough to match the other steels in toughness (20 Charpy C ft-lbs in above reference table).
I suspect that Phil Wilson didn't find there was a good tradeoff ... and that is why he used 10V instead. (I'm about to buy a hunting knife from Phil in either 420V at Rc 60-61 or 10V at 61-62... not sure just yet).
Reference: 15V: 3.4% C, 5.25% Cr, 14.5% V, 1.3% Molyb.
10V: 2.45%C, 5.25% Cr, 9.75% V, 1.3% Molyb.
Bailey Bradshaw and Darrel Ralph use 3V. Bailey in folders (custom, & his semi-production WhiteWing)... lockbacks, traditional slip joints, etc. Bailey might do a 10V folder on custom basis. I'm sure Paul Bos and Phil Wilson would heat treat the blades for him if he didn't think he wanted to tackle himself.
Austenizing temps are the real limiting factors. Anything past 2000F requires special treating (wrapping) foils and furnace coils.
420V: 2125F
440V: 2050F
3V: 1875-2050F
10V: 1950-2150F
15V: 2050-2150F
Try the search engine for possible leads:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=90667&highlight=10V
Crucible's literature says that CPM 15V has 50% better wear resistance than does their 10V.
And they claim 10V to be 4 times better than D2.
Of course, what you give up is toughness at a given level of hardness. From a chart on page 35 of the "Crucible Tool Steel & Specialty Alloy Selector" book:
Steel.............Charpy C ft-lb....relative wear resistance
===============================================
CPM15V..@Rc60.........10..................15
CPM10V..@Rc60.........20..................10
CPM3V...@Rc58.........85...................2.8
M2..........@Rc62.........20...................3
D2..........@Rc60.........20...................2
A2..........@Rc60.........40...................1.3
S7..........@Rc56........120...................0.5
(just in case, Charpy C notch test involves milling out a C shaped notch in a bar of steel, and measuring the sudden, impact force required to snap the piece, often with a swinging weight... a toughness test.)
S7 is used for jackhammer bits, for example.
So 15V is 1/2 as tough as 10V for (claimed) 50% increase in slicing/abrasion/wear resistance.
What I'd like to see is a chart showing how much 15V's wear resistance deteriorates when it is brouht down in hardness enough to match the other steels in toughness (20 Charpy C ft-lbs in above reference table).
I suspect that Phil Wilson didn't find there was a good tradeoff ... and that is why he used 10V instead. (I'm about to buy a hunting knife from Phil in either 420V at Rc 60-61 or 10V at 61-62... not sure just yet).
Reference: 15V: 3.4% C, 5.25% Cr, 14.5% V, 1.3% Molyb.
10V: 2.45%C, 5.25% Cr, 9.75% V, 1.3% Molyb.
Bailey Bradshaw and Darrel Ralph use 3V. Bailey in folders (custom, & his semi-production WhiteWing)... lockbacks, traditional slip joints, etc. Bailey might do a 10V folder on custom basis. I'm sure Paul Bos and Phil Wilson would heat treat the blades for him if he didn't think he wanted to tackle himself.
Austenizing temps are the real limiting factors. Anything past 2000F requires special treating (wrapping) foils and furnace coils.
420V: 2125F
440V: 2050F
3V: 1875-2050F
10V: 1950-2150F
15V: 2050-2150F
Try the search engine for possible leads:
http://www.bladeforums.com/forums/showthread.php?s=&threadid=90667&highlight=10V
Cliff Stamp
BANNED
- Joined
- Oct 5, 1998
- Messages
- 17,562
rdangerer :
Last I heard he was running it at the same RC as 10V, ~ 63 RC. Running 15V any softer would not really help the situation, just shift the problem elsewhere. At a much softer RC the 15V blade would now see faster edge loss over the 10V one by deformation / impaction and the wear resistance would be of little/no use. Phil is still working with it as far as I know, and he is not one to push experimental blades on customers. Until he gets a solid base of work done with 15V, I would assume he would suggest 10V.
In regards to the steel, a 50% increase in wear resistance sounds impressive, but wear resistance is not the only factor in edge holding. What I would be concerned about is would you see excessive edge cracking with 15V. If you had to drop the hardness to prevent this, you would be better off with 10V. I have spoken to makers who have tried some really high alloy steels (T15), and this was the main problem. You either end up running the steel soft, or having a blade that can basically only cut meat.
I am getting a 15V blade from Phil similar to my 10V one, I will be curious to see if there is a functional difference in the edge durability, and if so just how "light" duty will the 15V blade one be, and how much functional gain is there in the edge holding due to the increased wear resistance.
-Cliff
Last I heard he was running it at the same RC as 10V, ~ 63 RC. Running 15V any softer would not really help the situation, just shift the problem elsewhere. At a much softer RC the 15V blade would now see faster edge loss over the 10V one by deformation / impaction and the wear resistance would be of little/no use. Phil is still working with it as far as I know, and he is not one to push experimental blades on customers. Until he gets a solid base of work done with 15V, I would assume he would suggest 10V.
In regards to the steel, a 50% increase in wear resistance sounds impressive, but wear resistance is not the only factor in edge holding. What I would be concerned about is would you see excessive edge cracking with 15V. If you had to drop the hardness to prevent this, you would be better off with 10V. I have spoken to makers who have tried some really high alloy steels (T15), and this was the main problem. You either end up running the steel soft, or having a blade that can basically only cut meat.
I am getting a 15V blade from Phil similar to my 10V one, I will be curious to see if there is a functional difference in the edge durability, and if so just how "light" duty will the 15V blade one be, and how much functional gain is there in the edge holding due to the increased wear resistance.
-Cliff