Foil wrap failure

I let the plates cool the blades 3 minutes, then check straightness, hardness, and give the oven time to settle the temp. How does one get full contact with flat plates and tapered blades? They cool to hand touch in three minutes. I only have one set of plates. I cannot "move on" until I get the one at hand taken care of. One plus to the entire matter is absolutly no warp. I did 4 more today, with one failure just as before. It is decarb. The steel under the soft is hard, but we are talking major decarb as much as .030 or more.
 
I take them out one at a time. I only one set of plates. I leave them in the plates for 3 minutes. At that point they can be handled bare handed. I check them over, check for warp, check hardness. Then let the oven temp settle. That takes about 8 minutes. How do you get full contact with plates that are flat, and blades that are tapered? I do not see any reason to worry about full contact as it is the cooling speed which counts, and 3 minutes is fast for an air cooling steel. I did 4 today. #1 was great. #2 had a little blue color and softness on the spine from the point back about 3/4". #3 was bad. Major decarb from the point back about 2". Decarb was at least .015 deep or more, but there was hard steel under it. # 4 was Ok, but the very tip of the point was blue, and one side had minor decarb and a bit of scale, but the opposite side did not! How do you figure that happened?
 
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LRB said:
I take them out one at a time. I only one set of plates. I leave them in the plates for 3 minutes. At that point they can be handled bare handed. I check them over, check for warp, check hardness. Then let the oven temp settle. That takes about 8 minutes. How do you get full contact with plates that are flat, and blades that are tapered? I do not see any reason to worry about full contact as it is the cooling speed which counts, and 3 minutes is fast for an air cooling steel. I did 4 today. #1 was great. #2 had a little blue color and softness on the spine from the point back about 3/4". #3 was bad. Major decarb from the point back about 2". Decarb was at least .015 deep or more, but there was hard steel under it. # 4 was Ok, but the very tip of the point was blue, and one side had minor decarb and a bit of scale, but the opposite side did not! How do you figure that happened?
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Decarb simply means there was a large enough hole for Oxygen to get in. Did not realize your tang was tapered. that would be interesting to try to get full contact on the plates!

colors again are normal. it's just from oil that wasn't wiped off or there was oil on the SS foil. again, no big deal. Gray is fine too.

again, i would just better your crimps. You can only make mistakes and learn and since we can't see first hand what happened, it's hard to say! But again, it's always a learning curve. What kind of SS Foil you using? 321 or 309? Some people only swear by 309, but again, that's some people. I have used 321 for years now and has always worked great and is a hell of a lot less $$. I buy it from www.lyonindustries.com something like $190.00 + shipping for 200 square feet.
 
There was no oil. The blades were cleaned well before wrapping, and the colors are always on the ends. Never in the middle. I am going to suspect the seal on the foil. The owner of the blades has done all the wrapping. I will wrap them myself next go around. LUE, I really appreciate your input. You have gone above and beyond to answer my problem. METE', Thankyou also. I have learned much from you and Kevin in past few years. More than the previous 30! Thank you both for trying, but it appears this is a problem I will have to experiment with to get the real answer. If either of you think of something else, please let me know. Thanks again. Wick Ellerbe
 
You fold and crease, fold and crease again.Try to get most of the air out.To crease just run a piece of metal along the folded edge.
 
LRB

I have noticed that opening and closing the door allows the sealed envelope to "breath" a bit as the air inside expands and contracts. This often leads to blades with a littlle more oxide (the blue) than the first blades out. In my case, I only do up to six blades at a time because that's all I can plate at once. (Big plates).

That won't help with your soft spots, but it may explain the blue on the later blades.

Plate quenching works fine, even with tapered tang. The cooling is still way faster than in air.

Like the others, I'm stumped over your soft spots. :confused:

Hope the re-run works for you.

Rob!
 
Leu, you say, "...cut open the foil packet, check for straightness..."
Can you straighten the blade at that point?
I'm comfortable doing that with 1095 and such, and wonder if the cooling curve on air quenching steels allows that.
Thanks!
Andy G.
 
Straightening can be done after the temperature drops below the pearlite nose but above the Ms .In that area [ see the TTT diagram for the steel] it's austenitic.After the steel has completely cooled then straightening should only be attempted at temperatures of 400 F or higher.
 
Do not cut open the foil packet till all the visible red heat is GONE...otherwise you run the risk of getting decarb on your blade.

I have used A2 since pretty much the beginning...what I learned is, pretty much anything above 1/8" thick..you can straighten...Even the next day!!! it won't break! even if it's been at room temperature for hours and hours! I used to cut open the foil packet and then immediately check for straightness...however, this method you can end up dropping the blade, burning yourself, etc. Obviously the thicker the steel is with A2 you would need an arbor press to straighten it...but it can still be straightened so long as you haven't tempered it. You could straighten it after temper, but you'd have to over bend the hell out of it to straighten..which i don't advise! (and this post was started 14+ months ago! lol)

now as far as 1095, i have no idea. I would think steels that have been quenched in something, water, oil, etc etc...could break if you tried to straighten then below 400 degrees or at room temperature. But the Air hardening steels, seem to resist breaking
 
I have a question, and I did not read this if it was mentioned. Do you remove the blade from the foil before plate quenching, or quench with the blade in the foil?
 
I get the discolor most of the time on my A-2 but they are not soft but then again I do not grind too thin before the H.T . I spray mine with wd-40 and then put them in the foil . I usually try and do 6 at a time , plate quench 2 at a time . Never have figured out why the discolor but no harm done so I don't worry about it . Then again my steel 5/32"
 
melsdad said:
I have a question, and I did not read this if it was mentioned. Do you remove the blade from the foil before plate quenching, or quench with the blade in the foil?
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generally the knife (still in foil) is taken out of the kiln and put between two plates, quenched until it's room temperatureand then taken out of the plates and the foil packet cut open. This does not guarantee straightness!
 
it's discolored because there's oil on the surface or on your stainless foil packet inside. if everything is super tight and air free and the blade has been wiped down and also the inside of the foil packet degreased, the blade should almost come out the same exact color it went in. it doesn't hurt anything though with the discoloration and is actually easier to get off via buffing or regrinding on the flats and bevels. If you heat a piece of A2 with a torch to lets say cherry red and wait till it cools to room temperature by itself, it turns gray/colored etc...so also, it has to do with the foil packet having a little bit of a leak (i think)
 
Thanks for clearing that up Leu! I plan on doing some plate quenching in the near future, and I figured that is how it was done. It would seem to me you would waste to much time between furnace and quenching if you had to unwrap the blade first.
 
Be aware that if your grinds aren't even (like a chisel ground blade) Plate quenching can cause WARPING! But not the warping we normally think about. It can cause a blade to develop a curve in the spine or in reverse! Generally with stuff 1/8" or thinner...maybe even 5/32" thickness and no more than 1-1/2" wide blade
 
I have experienced this same thing with 3v, pretty much word for word as you have described it. Decarb is the only answer that makes sense once you narrow it down. My first question is did you buy a roll of foil or get it by the foot, and folded up? And where did you get it from?
 
Justin King said:
I have experienced this same thing with 3v, pretty much word for word as you have described it. Decarb is the only answer that makes sense once you narrow it down. My first question is did you buy a roll of foil or get it by the foot, and folded up? And where did you get it from?
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if you are asking me, i buy the foil by the roll. 2 feet by 100 feet. It's probably the best priced stuff i've found and is very well made. Have never had it weld to my blades either. I use type 321 since i only really ever heat treat to 1800 for A2 and 1900 for CPM 154. I get it from http://www.lyonindustries.com/index...&category_id=1&option=com_virtuemart&Itemid=3. They carry 321 and 309, but their 321 has never failed me and it can go to 2000 degrees. Discoloration is not decarb is it? To me decarb is only when the steel is flaking off.
 
Discoloration is oxide colors like temper colors. If it's flaking off it's not steel but scale [iron oxide ] !! if there is scale there will be a layer of decarbed steel underneath ! Scale , flaking or not can be removed by soaking in acid such as HCL .Get it at a hardware store as concrete cleaner. The decarb must be removed by grinding .
 
mete said:
Discoloration is oxide colors like temper colors. If it's flaking off it's not steel but scale [iron oxide ] !! if there is scale there will be a layer of decarbed steel underneath ! Scale , flaking or not can be removed by soaking in acid such as HCL .Get it at a hardware store as concrete cleaner. The decarb must be removed by grinding .
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Thanks mete! I remember back in the day removing decarb with distilled white vinegar. Or did i? lol
 
I kept having problems with my foil sticking to the blade. 309 foil and D2 at 1850. I was cleaning the blades off real well then making a tight envelope. If I put a very light film of WD40 no sticking issues. I do get some coloring, but, that comes right off.
 
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