Do blade coatings slow quench speed?

D

Darrin Sanders

Moderator
Does anyone know if blade coatings like a Satanite wash, ATP-641, or PBC slow down quench speeds? If so is it slowed enough to effect blade performance? Been wanting to try some of these but wanna be sure performance isn't compromised. Thanks.
 
Yes, I believe it's gonna have an impact on quench speed. How much of an impact will probably depend on the "small details".
Can't speak for how much of a difference a certain coating will affect a certain steel in a certain quenchant.

But I do know that if I want a differentially-hardened blade made in Japanese fashion, partially coating a shallow-hardening steel with Satanite is a good way to do it.
 
Good question. I would think that if it did, it would only be a concern with steels of the 10XX types that require a very fast cooling quench. There is little need to use it on those as most leave them a bit over sized anyway to prevent cracking, and they will need more grinding after the temper. 10XX steels do not require any lengthy soaking at high heat so decarb is not a great concern either. I use ATP on a regular basis for 01, and it has no effect on it. When it comes out of the oil it is shiny smooth and there is no decarb. The ATP allows me to take my 01 blades to finished dimensions, and only requires a simple clean up to get them ready for the grip.
 
Steels that require rapid quenches like 1095 & W2 were what I was wondering about. The idea of taking blades to finished dimensions and 400X or so finish with a quick cleanup after H/T is why I'm thinking of trying it. May have to get a little O1 and give it a try. Thanks.
 
I did a test on leatherworking round knives for a customer - one done with turco - one done with ATP641 - one done without ptotection - all thin O1 - all got 20 minutes at 1500F.

There was little difference in RHC hardness - and I tempered tham all back to RHC 60 together.

My customer did not like the ATP641 - and saw no difference between Turco and no protection at all. I still use turco on most blades -just because - but I think if you are expecting a cleaner blade - from a kiln - you may be disappointed. Forge may be different.

Rob!
 
Mine are cooked in an Evenheat oven for 20 to 30 minutes at 1475°, then quenched in Parks AAA. As I said, mine come out very clean and shiny with only colors like case hardening on them. They are smooth enough to just hand sand to finish. When I apply the ATP I let the blades sit over night, then touch up any places that show through before they go in the oven.
 
Last edited:
I would think they would slow the cooling rate of the blade but more significantly it can increase the chance of blade warpage as a result of uneven cooling. If the material breaks away from the blade unevenly then you will have uneven cooling.
 
Any warpage I get is minimal and easily hand straightened while the blade is still warm. Flakes from the ATP coating after HT are only a few thousandths thick. I can see no downside when used with 01.
 
I used PBC and was not happy when I got a lumpy bumpy coating. That said the knives came out looking great and I could not detect any visual difference after etching the damascus pattern. Ferric chloride easily reveals hardness differences when I use Rutland furnace cement (for hamon) so I think the PBC works as advertised in spite of the huge thickness variations.

ernie
 
I have also used the PBC with fine results, but for me, I find the ATP easier to apply. Does as good or better in it's intended purpose. Also, a jar of it goes a long way.
 
use the liquid. I found that if you leave a blob of the powdered stuff on the blade, you may end up with pitting.
clancy said:
I used PBC and was not happy when I got a lumpy bumpy coating. That said the knives came out looking great and I could not detect any visual difference after etching the damascus pattern. Ferric chloride easily reveals hardness differences when I use Rutland furnace cement (for hamon) so I think the PBC works as advertised in spite of the huge thickness variations.

ernie
Click to expand...
 
LRB said:
Good question. I would think that if it did, it would only be a concern with steels of the 10XX types that require a very fast cooling quench. There is little need to use it on those as most leave them a bit over sized anyway to prevent cracking, and they will need more grinding after the temper. 10XX steels do not require any lengthy soaking at high heat so decarb is not a great concern either. I use ATP on a regular basis for 01, and it has no effect on it. When it comes out of the oil it is shiny smooth and there is no decarb. The ATP allows me to take my 01 blades to finished dimensions, and only requires a simple clean up to get them ready for the grip.
Click to expand...

Wick what is ATP and how are you using it?
 
LRB said:
I have also used the PBC with fine results, but for me, I find the ATP easier to apply. Does as good or better in it's intended purpose. Also, a jar of it goes a long way.
Click to expand...

LRB, where are you getting your ATP? I've been looking for some to replace the sanitite wash as it dirties up my oil too quickly.
 
I'd like to try the ATP sometime simply due to the thickness of the PBC on a blade makes it difficult to see a warp right out of the quench. I've found that if I have the hot water running when I take the blade coated with PBC out of the quench still slightly smoking and put it under the running hot water to remove the already flaking off PBC I can quickly straighten the blade in a vice and check it on the flat granite block. I've had good luck that way. Any remaining warp can be usually ground away.

For gun parts I cant do without PBC. I can take the hammer and trigger right to perfect size and 400-600 grit and coat them very heavy (1/8") to prevent any pitting from non-coverage and they wash perfectly clean again in boiling water. The thick coating doesnt seem to be an issue with hardness variations.
 
You must log in or register to reply here.
Back
Top