Orange Peal

gnique

gnique

Joined
Apr 25, 2007
Messages
59
I just pulled an O1 steel blade out of my brand new Even Heat oven and large flakes of scale came off of it. The scale was black and came off in pieces that were very thin - like paint except much thinner. When I put it on my buffer I found that the whole blade had been etched to an orange peal like finish. This has never happened to me before. Does anyone have any help? My only thought is that I should have cleaned the blade better before I heated it. I hate making mistakes! I hate gaining experience! I hate education! I hate learning new stuff! Why can't all the things that I do in life turn out perfect! There - I feel better now. Once again, the same old story that I have heard and experienced 10,000 times before - I will probably learn something from this experience. I really don't mind saying that to my kids but I hate it when it applies to me. Anyway - ideas? What did I do wrong THIS time. Thanks - Nicholas Jasper
 
Did you not wrap it in Stainless foil? realy sounds like it got too hot to me but I dont know that much about O1.
 
That's pretty normal when pulling an unprotected blade out of an oven. Most of that stuff flakes off in the quench when hardening. If you want to prevent it, you've got to use something like a PCB powder or stainless foil (for air hardening steels).

--nathan
 
Too hot? How hot is too hot? I set my oven to 1475. Is there a way to know if the temp controller is accurate? No I did not wrap in SS foil. I never have. Should I?
 
It's not too hot , just oxidation. Foil is not much help with an oil hardening steel as you would have to remove the foil to quench. Try the PCB .
 
I've done O1, did not wrap in stainless foil, no flaking or orange peels here. Just some mild scale.

mete said:
It's not too hot , just oxidation. Foil is not much help with an oil hardening steel as you would have to remove the foil to quench. Try the PCB .
Click to expand...

What is PCB?
 
PCB is a compound you use to coat the blade during the heat treat process. It melts to the blade and creates an oxygen barrier to prevent oxidation/scale/decarb.

--nathan
 
It's PBC, manufactured by Rosemill.
It can be purchased in 1 pound quantities from Brownells.

There is also a liquid (suspension) anti-scale called ATP that is also carried by Brownells.
 
Fitzo is right, or course...PBC powder. You know, I never could keep those letters straight. :)

--nathan
 
Thanks everyone. I just GOT a bucket of PCB but decided to NOT use it on my first run in the oven cause I didn't want to introduce two variables. Orange peel doesn't look bad to me but it might to anyone else. I guess I'll have to get ANOTHER knife block; I'm out of slots. I like the oven and the soak times - it gives me time to read and smoke cigars.
 
gnique said:
Thanks everyone. I just GOT a bucket of PCB but decided to NOT use it on my first run in the oven cause I didn't want to introduce two variables. Orange peel doesn't look bad to me but it might to anyone else. I guess I'll have to get ANOTHER knife block; I'm out of slots. I like the oven and the soak times - it gives me time to read and smoke cigars.
Click to expand...

I really suspect if it is real "orange peel" effect like D2 has... I guess they are just oxidation and decarburization layers. Just sand them off, you dont want to keep them on your blade, they rust easily, they are soft and promote pitting...

Emre

edit: at least that is what i do for my knives. The scale is ok to leave on the blade as it is really tough layer. But underneath the layer those grayish thin layers are not so durable as far as I know...
 
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Thanks fitzo and silver_pilate. Looks like I'll be getting some PBC!

gnique said:
Thanks everyone. I just GOT a bucket of PCB but decided to NOT use it on my first run in the oven cause I didn't want to introduce two variables. Orange peel doesn't look bad to me but it might to anyone else. I guess I'll have to get ANOTHER knife block; I'm out of slots. I like the oven and the soak times - it gives me time to read and smoke cigars.
Click to expand...

In the case of O1, you should be getting good results w/o any treatment prior to heat treat. I left the scale on my knife and it has been cutting for months w/o the scale flaking off. It works like a teflon coat. Something else is wrong.
 
cotdt,

You will still get the oxidation flaking on the blade in most cases if not protected, but it's not a big deal.

gnique,

I'm not sure I understand why you think you've ruined a blade. Just grind/sand the blade smooth, and you're good to go. With any carbon steel, you will have to refinish after heat treat unless you protect them with something, and even then, there is clean up work to do.

--nathan
 
I have a couple (few?) suggestions.

  • Don't put the blades in from cold. If you can time them about 15 minutes from your high temp, they should soak at temp long enough without sitting too long in the zone.
  • Consider some level of protection for the blade that you don't have to remove for quenching (like PBC or similar products)
  • If you do HT an unprotected blade, leave some meat there to grind away later. There is bound to be some decarb.
As for your evenheat, it is accurate almost for sure - but accurate at the thermocouple. There will be 25 - 50 degrees variation at different points inside the chamber. You can buy a meter and thermocouple to test throughout - or you could just increase temps by about 25 degrees and you'll generally be very close to "the zone".

I know you don't want to hear this - but here it is again.

Heat treating is science - but there is an art to getting the science right. ;) Your customers don't respect you because you did it yourself. They respect you because you did it yourself and got it right.

Rob!
 
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