anyone harden PTG dies in kiln?
- Thread starter alinwa
- Start date
I don't know of any industrial applications that are analogous and I've friends/relatives in the business of mfg for industry. I try to stay current.
To the best of my ability I've followed them and investigated them all for 15yrs..... I know of no deposition process that will work. If you can suggest one that
(A) builds evenly/repeatably on all surfaces and planes including inside corners
(B) won't separate from substrate under pressure
(C) is Rockwell 'C' 55 or harder
(E) is adaptable to small lots
I'm all over it!
al
See here's where I'm confused......
I've spoken with Dave Kiff several times. Any more and I'd be bothering him, he went over the entire process with me. He's done it. He's made dies AND gave detailed description as to how he made the crimping pliers for sealing the bags and how to wrap the parts. And where to buy the foil and how much to pay..... in short, Dave has been very helpful and generous (as always!) with his time.
But I keep thinking I may have mis-heard him as all this flies in the face of what I "know" about heat treating. And what I "know" is that I don't dare quench the dies I've turned out!
I don't wanna' wreck 'em.
I'm picturing an agitated oil bath quench brought up to a couple hunnerd degrees, "gentle" insertion using tongs and a knife onto a pre-heated popcorn popper plate and swirl into the oil, hot spatter ever'where....
nahhhh
meloniting is coming back into focus, for me!
LOL
al
I've spoken with Dave Kiff several times. Any more and I'd be bothering him, he went over the entire process with me. He's done it. He's made dies AND gave detailed description as to how he made the crimping pliers for sealing the bags and how to wrap the parts. And where to buy the foil and how much to pay..... in short, Dave has been very helpful and generous (as always!) with his time.
But I keep thinking I may have mis-heard him as all this flies in the face of what I "know" about heat treating. And what I "know" is that I don't dare quench the dies I've turned out!
I don't wanna' wreck 'em.
I'm picturing an agitated oil bath quench brought up to a couple hunnerd degrees, "gentle" insertion using tongs and a knife onto a pre-heated popcorn popper plate and swirl into the oil, hot spatter ever'where....
nahhhh
meloniting is coming back into focus, for me!
LOL
al
D
David Merrill
Guest
Metallurgy
Best free, not too technical, basic steel metallurgy education that I've chanced across on the Web:
http://www.feine-klingen.de/PDFs/verhoeven.pdf
Another decent source for amateurs:
http://www.bladeforums.com/forums/s...etta-Stone-of-Metallurgy-Lots-of-HT-info-here
Note that both of these are slanted somewhat toward the specific range of steels preferred by knife makers but the background basics are there. I wouldn't spend a lot of resources trying to heat treat any steel until you understand a TTT diagram and get a copy of one for the steel in question (DAGS '4140 TTT OR CCT' on Google Images).
Random bits of grist for the mill: one of the main reasons for incorporating steel alloying elements (chromium & molybenum in 4140) is to push the 'nose' of the TTT curve to the right allowing more time to cool below the nose before the carbon dissolved in the austenite has a chance to start changing to undesireable things. Realize that, during the quench, the cooling rate of the interior of the workpiece lags that of the surface. Hence, 'low alloy' steels like 4140 will fully harden in thicker section than plain carbon steels -- read about hardenability tests and the resulting curves. (There are also other reasons for adding alloy elements.) Steel can be thought of a a (particulate) composite material. 'Soak time' at the austenitizing temperature is needed to allow the carbon to dissolve uniformly throughout the austenite. Too high an austenitizing temperature will encourage coarse rather that fine crystal grains to form, leading to generally lower toughness in the final Q&T product (may be unimportant re: loading dies).
Yes Al, I suspect you have misunderstood your die blank supplier, you have described temperature and cooling rates typical of annealing for purposes of machining rather than heat treatment for the purpose of hardening.
David Merrill
Best free, not too technical, basic steel metallurgy education that I've chanced across on the Web:
http://www.feine-klingen.de/PDFs/verhoeven.pdf
Another decent source for amateurs:
http://www.bladeforums.com/forums/s...etta-Stone-of-Metallurgy-Lots-of-HT-info-here
Note that both of these are slanted somewhat toward the specific range of steels preferred by knife makers but the background basics are there. I wouldn't spend a lot of resources trying to heat treat any steel until you understand a TTT diagram and get a copy of one for the steel in question (DAGS '4140 TTT OR CCT' on Google Images).
Random bits of grist for the mill: one of the main reasons for incorporating steel alloying elements (chromium & molybenum in 4140) is to push the 'nose' of the TTT curve to the right allowing more time to cool below the nose before the carbon dissolved in the austenite has a chance to start changing to undesireable things. Realize that, during the quench, the cooling rate of the interior of the workpiece lags that of the surface. Hence, 'low alloy' steels like 4140 will fully harden in thicker section than plain carbon steels -- read about hardenability tests and the resulting curves. (There are also other reasons for adding alloy elements.) Steel can be thought of a a (particulate) composite material. 'Soak time' at the austenitizing temperature is needed to allow the carbon to dissolve uniformly throughout the austenite. Too high an austenitizing temperature will encourage coarse rather that fine crystal grains to form, leading to generally lower toughness in the final Q&T product (may be unimportant re: loading dies).
Yes Al, I suspect you have misunderstood your die blank supplier, you have described temperature and cooling rates typical of annealing for purposes of machining rather than heat treatment for the purpose of hardening.
David Merrill
THAN YOU'SE
THANK YOU'SE!!
THANK YOU'SE!!!!
I have NO- nada-ZERO interest in learning all about tempering alloyed steels at this point in my life. I know just enough to know that it's a larger proposition than I'm interested in. Heck, I'm a hobbyist, a backyard tinkerer not a gunsmith.
You've all convinced me that it's a larger proposition than buying a little furnace.
I don't even want a set of salt tanks and I know the ins and outs of hot-bluing.... but there are always 5-8 guys within 20mi that do fire up the baths ever' month or so. And there are heat-treating shops and ionizing/hard-chroming/nitriding/anodizing shops scattered all over Vanc/Portland Metro. Just yesterday I talked with a shop that does gas nitriding....
Until someone convinces me that "air-hardening" isn't just a figment of my personal delusions I'm gonna' relax on the subject
thanxagain
al
THANK YOU'SE!!
THANK YOU'SE!!!!
I have NO- nada-ZERO interest in learning all about tempering alloyed steels at this point in my life. I know just enough to know that it's a larger proposition than I'm interested in. Heck, I'm a hobbyist, a backyard tinkerer not a gunsmith.
You've all convinced me that it's a larger proposition than buying a little furnace.
I don't even want a set of salt tanks and I know the ins and outs of hot-bluing.... but there are always 5-8 guys within 20mi that do fire up the baths ever' month or so. And there are heat-treating shops and ionizing/hard-chroming/nitriding/anodizing shops scattered all over Vanc/Portland Metro. Just yesterday I talked with a shop that does gas nitriding....
Until someone convinces me that "air-hardening" isn't just a figment of my personal delusions I'm gonna' relax on the subject
thanxagain
al
X
xs hedspace
Guest
A piece of wood in the foil sounds better that an old recipe I found in a blacksmith's handbook from the 1890's. Some ingredients in the packing box for case hardening included hoof trimmings, old harness leather, rock salt, and horse urine. I actually tried case hardening, using bone charcoal, wood charcoal, and leather scraps. Wifey thought I was cremating the dog---cooked it at 1400 deg in an old pottery kiln outside. Found that the sealed container actually produces cyanide gas, for the nice colors, dropped the idea after two tries.
The chroming shops I've talked to indicate that chrome goes on unevenly, varying in thickness even on the open surfaces but made worse, MUCH worse by the internal configuration of a die........ especially building up at the inside corner radii.
al
S
Stonewall
Guest
If that company was Armoloy in Texas stay well clear of these people.
They sandblasted in prep for plating two rifle actions for me in 1992 with the result that they were completely destroyed .
Their only comment was that they were not a gunsmith.
I have worked on plastic molds and this product would not be suitable there.
Glenn
They sandblasted in prep for plating two rifle actions for me in 1992 with the result that they were completely destroyed .
Their only comment was that they were not a gunsmith.
I have worked on plastic molds and this product would not be suitable there.
Glenn
Electroless nickel plating looks fairly good on paper compared to hard chrome. I spoke with a company who does it, and they thought they could plate the inside of a die evenly... But, they had never tried before
I guess the problem with all platings/coatings is that the steel below is still fairly soft, al long as it´s not hardened before coating/plating. You could run into flaking problems if the die isn´t hard enogh underneight the surface.
I guess the problem with all platings/coatings is that the steel below is still fairly soft, al long as it´s not hardened before coating/plating. You could run into flaking problems if the die isn´t hard enogh underneight the surface.