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-   -   Quench fail. What now? (http://www.knifenetwork.com/forum/showthread.php?t=68131)

Rasmus Kristens 04-20-2018 02:27 PM

Quench fail. What now?
 
Hi all

I just tried hardening my first o1 blade.
The quench didnt go as planner. I tried
using a gas roof burner, but it turned out to be pretty difficult to control and it didnt burner as hot as I imagined.
After the quench part of the blade didnt harden.

I usually use charcoal and hairdryer, which aparently burns hotter.

What do I do now? Can i just tak it to quenching temperaturen and try again or should i normalise it a few times first?

What Will the end result be because of This mistake? Will i feel Any difference in the over All heat treat when its just backyard hardened?

Ray Rogers 04-20-2018 04:51 PM

I'm not sure where to start with this. Apparently, you have had some success with charcoal and a hair dryer (proof that almost any heat treatment of O1 will make a passable blade). If you want to try gas then build a regular forge, it's pretty easy, cheap, and fast to do and it will absolutely work.

To re-heat treat that same blade I would suggest that you start by annealing it. I don't know that it is absolutely necessary but O1 is a moderately alloyed steel so I'm sure it would not hurt to do that step. Get the largest container of wood ash, vermiculite, or kitty litter that you can find (I use 55 gallons of wood ash). Heat the blade above the quenching temp and bury it in the center of the container, leave it over night. If you do that then this blade should come out about the same as any other O1 blade that you have done ...

Rasmus Kristens 04-20-2018 05:00 PM

Okay, so i did something.
I fires up the barbecue and put the blade in the coal. I took it just below non magnetic and let it cool slowly while i heated my canola oil.

When the blad was touchable, but above room temp, i heated it up to non magnetic and gave it a bit longer. My thermocoulpe like eyes told me i hit the 1500 F spot on ;-)
i didn't soak it for long.

It hardened real nice!
Its in the oven right now tempering at 410 F for 2x 1 hour.

Can someone explain how a knife novice like me can feel or see a difference in a not properly heat treated blade? Can i do some kind of test on the blade without breaking it?

Rasmus Kristens 04-20-2018 05:07 PM

Ohh didn't see your poste before i posted mine.
Well.. Atleats its good to know i stille have a lot to learn :-)

Ed Caffrey 04-20-2018 05:10 PM

A VERY rudimentary test for hardness is a NEW file. If the file skates off without cutting, you're got at least a certain level of hardness. If the file cuts, then you've missed the mark.

The good news is that O1 is pretty forgiving of errors. Unless you way overheat it, you've got at least a couple of chances to harden it.

"Seeing" if something is hard is impossible, but there are certain visible indicators. Namely, when the scale "blows" off during the quench. This is due to the steel contracting slightly, but the scale does not....so it falls off. This is by no means any indication that you nailed it....only that where the scale came off, it hardened to a degree.

jimmontg 04-20-2018 10:13 PM

I might add Rasmus, if it's available to you in Denmark, is to try and get O1 with the 0.20% vanadium in it. It doesn't add hardness at that low percent, but it does help to keep grain growth down as it strongly promotes a fine grain. Makes the O1 even more forgiving. The sweet spot temperature for O1 is 1475 by the way. 1425 to 1550 will give you a nice hard knife with O1.
When I started making knives it was with O1 and a charcoal forge the same as you.

Rasmus Kristens 04-21-2018 12:26 AM

thanks all.

The knife did harden fine when doing the file test.
jimmontg, i bought some O1 frok UK, i cant find it in Denmark, and it does contain 0,20% Vanadium :-)

I think one of my questions is, will it make sense for me to pay for shipping and professional HT when i'm just doing it as a hobby?
I see a lot of you experienced guys talking about getting the best out of the steel, but for me going camping 2 times a year, would i feel a difference in the blade with a professional HT?

dtec1 04-21-2018 08:20 AM

my personal opininion (and this is the way i learned......as ray said a forge is very simple and cheap to make (ray has a video on how exactly to build a cheap forge talk to him about that) So i made a couple forges the one i use now is for dammascsu as i don't forge my blades or HT them in there but essentially it is a small air compressor tank that i cut both ends off off drilled 2 holes in the side on the right angles to insert the burners then the floor is done with HARD fire brick and then inswool or kao wool is put in the forge to cover everything else but the floor and then satinite is painted onto the wool..this thing works great...now each steel is different so pick 1 steel to learn first and this is how it was tought to me (and this is a quick run down ask questions to elaborate when you get there) it worked great first i made a couple "coupons" all that is a small rectangular piece of steel that you basicly pretend it is a blade and heat treat it....check it with a file to make sure it is hard then temper it then put it into a vise and hold on to the other end with large plyers to give you leverage....pull down and break that coupon in half....first note how much of a angle it bent before it snapped then check the grain....you may have to do this a couple times to get the best results but once you do then make a blade and heat treat it exactly as you did with the coupon finish the blade and test it do cutting test see how long it takes to get dull cutting rope cardboard what ever stab it into something and pull out....write things down so you can compare with the next blade

jimmontg 04-22-2018 12:48 AM

Rasmus, it isn't in your best interest to send out O1 for HT. You go camping a couple of times a year? I doubt you'll notice any difference as long as you don't temper the blade back too far. If I remember correctly I had a couple of knives that a file would barely bite into after a temper at 400 degrees for 2 hours. Must have got them good and hard.

My S30V filet knives are very wear resistant and my customers in Florida wanted that. The very first knives I made were from files I tempered back and ground for working on a fishing boat in the 70s. I was tired of constantly having to resharpen my knives from cutting through bones and scales. Those file knives were very hard and held up well. Not too easy to sharpen, but I was a pro at that.

The first filet knife I sold was O1 and the skipper of the boat was impressed by how many fish it filleted without sharpening. That was HT in an oven, so don't be surprised if you don't get a few blades that good too. By the way, O1 does better with a longer soak if you can keep the charcoal from getting too hot. You might try to experiment by getting the steel a bright cherry red and then turn down the air blast a little and try to maintain that color for a few minutes.
Good Luck.

epicfail48 04-22-2018 04:02 AM

Quote:

Originally Posted by jimmontg (Post 496669)
Rasmus, it isn't in your best interest to send out O1 for HT. You go camping a couple of times a year? I doubt you'll notice any difference as long as you don't temper the blade back too far. If I remember correctly I had a couple of knives that a file would barely bite into after a temper at 400 degrees for 2 hours. Must have got them good and hard.

My S30V filet knives are very wear resistant and my customers in Florida wanted that. The very first knives I made were from files I tempered back and ground for working on a fishing boat in the 70s. I was tired of constantly having to resharpen my knives from cutting through bones and scales. Those file knives were very hard and held up well. Not too easy to sharpen, but I was a pro at that.

The first filet knife I sold was O1 and the skipper of the boat was impressed by how many fish it filleted without sharpening. That was HT in an oven, so don't be surprised if you don't get a few blades that good too. By the way, O1 does better with a longer soak if you can keep the charcoal from getting too hot. You might try to experiment by getting the steel a bright cherry red and then turn down the air blast a little and try to maintain that color for a few minutes.
Good Luck.

I second this. A commercial heat treat service will do an excellent job treating the steel to industry standards and wringing the best performance out, yes. That said though, something like O1 is designed to get that same performance when heat treated with down and dirty methods, so you arent going to miss it much. Now, some more complicated steel like s30v that requires a precise, high temperature soak at a certain time, followed by a liquid nitrogen tempermight be worth sending off, but simple carbon steels? Not unless you just flat out dont have the time or tools

Rasmus Kristens 04-25-2018 12:57 PM

Alwayse a pleasure asking questions here :-)
Dtec and Ray, you would be amazed how difficult and expensive it is to get these almost "American Household goods" in Denmark. ;-) What kind of torches do you have to use for a airtank forge?
Do you have a product name on the bricks? I can't really find anything.


Quote:

Originally Posted by jimmontg (Post 496669)
By the way, O1 does better with a longer soak if you can keep the charcoal from getting too hot. You might try to experiment by getting the steel a bright cherry red and then turn down the air blast a little and try to maintain that color for a few minutes.
Good Luck.

If i try soaking the blade for a bit, which temperature should i aim for? Is it just above critical or should i go the bit higher and try keeping it at quenching temperature?
Do i risk overheating if i do something wrong?

I will practice on a few small pieces.

Ray Rogers 04-26-2018 08:27 AM

You don't have to buy the torches for the forge, you can make them from a few pieces of pipe. Fire brick or any kind of ceramic meant to be used inside a stove would do for a floor. Ceramic wool should be available from any place that sells wood stoves or from some place that does repair work on commercial heating systems.

The soak temp would be the temp at which you want to quench.

Sure, you risk over heating but O1 is very forgiving so as long as the over heating isn't too bad you should still be OK ....

jimmontg 04-26-2018 11:35 AM

If i try soaking the blade for a bit, which temperature should i aim for? Is it just above critical or should i go the bit higher and try keeping it at quenching temperature?
Do i risk overheating if i do something wrong? [/QUOTE]

Like Ray said O1 is pretty forgiving about overheating as long as it isn't too extreme Rasmus. With the vanadium in it, your O1 is a little more forgiving. Try for just above critical, but make sure you stay above critical. With charcoal l think you shouldn't be in too much danger of over-heating once you turn your air blast down. I used to try to get a uniform color when I heat treated with charcoal and unknowingly made a better knife as a consequence. l did not fuss about the tang area, just the blade was all l was interested in heat treating.


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