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CPM-9V
- Thread starter GW
- Start date
- Joined
- Oct 16, 1998
- Messages
- 307
GW
9V looks great till you dig into the data at 58RC its toughness goes way down.
At 43RC it is up with 3v but it wont have the compression resistance to work for handheld knives.
10V , 3V, 440V or 420V are much betterchoices.
As to forging these steels it can be done I know that 420V is done commercially in
progressive dies and some smiths have done 440V with good results
Temp is very critical and annealing can be a real pain.
http://www.angelfire.com/ct/schottknives/
------------------
Edward Randall Schott
Knifemaker
edschott@rcn.com
[This message has been edited by Edward R Schott (edited 01-20-2000).]
9V looks great till you dig into the data at 58RC its toughness goes way down.
At 43RC it is up with 3v but it wont have the compression resistance to work for handheld knives.
10V , 3V, 440V or 420V are much betterchoices.
As to forging these steels it can be done I know that 420V is done commercially in
progressive dies and some smiths have done 440V with good results
Temp is very critical and annealing can be a real pain.
http://www.angelfire.com/ct/schottknives/
------------------
Edward Randall Schott
Knifemaker
edschott@rcn.com
[This message has been edited by Edward R Schott (edited 01-20-2000).]
I see your point but.....according to the data, 9V is "tougher" and more resistant to cracking/chipping than 10V, and only marginally less wear-resistant. Granted the 9V's attainable hardness is lower, but does this number rule it out entirely as a good knife steel? (given its's wear-resistance and toughness ratings)
How is 10V for forging, grinding etc.?
Thanks.
------------------
GW
How is 10V for forging, grinding etc.?
Thanks.
------------------
GW
- Joined
- Oct 10, 1998
- Messages
- 224
I've made one blade out of CPM 10-V, and am in the process of doing a couple others.
At first, I was reluctant, due to the fickleness of the HT, but decided to "go to the top of the mountain" & contacted Phil Wilson, who's written several articles on this stuff.
At that point, he had experimented with the 44-V, 420-V, & 3-V, but hadn't done the 10-V, but was willing to give it a go. Upon completion, he was very impressed....said that overall, it was THE toughest of the CPM family.
All I know is it eats belts a bit faster than other steels, it's a booger to get an edge on but once on it's sharp for a LONG TIME, and take it to the highest grit polish you can before HT, 'cause afterwards it's hard as ceramic!!!
At first, I was reluctant, due to the fickleness of the HT, but decided to "go to the top of the mountain" & contacted Phil Wilson, who's written several articles on this stuff.
At that point, he had experimented with the 44-V, 420-V, & 3-V, but hadn't done the 10-V, but was willing to give it a go. Upon completion, he was very impressed....said that overall, it was THE toughest of the CPM family.
All I know is it eats belts a bit faster than other steels, it's a booger to get an edge on but once on it's sharp for a LONG TIME, and take it to the highest grit polish you can before HT, 'cause afterwards it's hard as ceramic!!!
- Joined
- Oct 16, 1998
- Messages
- 307
Gw
The problem with 9V in knives is the edge being so thin it wont have the resistance to
deforming, there just is not enough material to hold up it will just bend and if you run the
hardness up so it wont bend it will chip badly.
Forging these steels as I said is done, the company I know that does it uses salt pots for heating and
annealing but with a 22hr run for 10V and a 24 hr run for 9V it would be hard to do in a
home shop.
They have to be cooled at a rate of 30F per hr max.
Harry are you sure Phil said 10V is the toughest the data doesnt suggest this.
As 10V has a charpy test of 26 ft-lbs at 59RC, and 3V is 85 ft-lbs at 58RC.
Ed
The problem with 9V in knives is the edge being so thin it wont have the resistance to
deforming, there just is not enough material to hold up it will just bend and if you run the
hardness up so it wont bend it will chip badly.
Forging these steels as I said is done, the company I know that does it uses salt pots for heating and
annealing but with a 22hr run for 10V and a 24 hr run for 9V it would be hard to do in a
home shop.
They have to be cooled at a rate of 30F per hr max.
Harry are you sure Phil said 10V is the toughest the data doesnt suggest this.
As 10V has a charpy test of 26 ft-lbs at 59RC, and 3V is 85 ft-lbs at 58RC.
Ed
- Joined
- Oct 10, 1998
- Messages
- 224
Ed-
You may be right! At the time (1998) Phil had written a couple articles on the CPM 440-V and 420-V....might not have had a chance to mess with the 3-V as yet. He definitely liked the 10-V over the higher chromium cousins for toughness, and wanted to play with some. IIRC, I gave him a 3"-4" piece to test on.....
One thing about the 10-V...it'll rust just like L6...while you watch!
Harry
You may be right! At the time (1998) Phil had written a couple articles on the CPM 440-V and 420-V....might not have had a chance to mess with the 3-V as yet. He definitely liked the 10-V over the higher chromium cousins for toughness, and wanted to play with some. IIRC, I gave him a 3"-4" piece to test on.....
One thing about the 10-V...it'll rust just like L6...while you watch!
Harry