Off Topic First yakut knife is soft after hardering.

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Kellny

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Apr 9, 2021
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Hi, i made my first yakut knife from material what i am using for making every single knife, its pin from tank T-34, it was looking good, i made everything right, it was looking good but now when i was hardering, (in the oil) the knife bend a bit, so i tried to make it equil, that was successful now its perfect so i went to sharpen it and when i was going to try how sharp it is i recognized its super soft, like i can bend the edge with my nail.
I tried to harden it again but now in water, nothing changed its still soft...
Do you think its repairable? Or bad material? I really dont know what to do now because i dont want to just throw it into trash after all hours i spent on the knife.
And sorry for my bad english, i hope that someone can help me.
 
Kellny said:
Hi, i made my first yakut knife from material what i am using for making every single knife, its pin from tank T-34, it was looking good, i made everything right, it was looking good but now when i was hardering, (in the oil) the knife bend a bit, so i tried to make it equil, that was successful now its perfect so i went to sharpen it and when i was going to try how sharp it is i recognized its super soft, like i can bend the edge with my nail.
I tried to harden it again but now in water, nothing changed its still soft...
Do you think its repairable? Or bad material? I really dont know what to do now because i dont want to just throw it into trash after all hours i spent on the knife.
And sorry for my bad english, i hope that someone can help me.
Click to expand...

Was it a track pin fron the actual tank you used? I have no idea what steel they are made from, do you know if they are high carbon steel or not? if you have some material left over do some tests on it. You can do a quench and snap test, this one is common for people who use old reclaimed steel, just quench it (don't temper) then get a hammer and try to whack a chunk off, if it shatters and breaks off clean then it has enough carbon to make a knife. Second test is get an angle grinder or something similar and look at the type of sparks that come off of it.
If the sparks "explode" like little fireworks and stream off into multiple directions then that indicates high carbon content. If you just get fine streams with no mini explosions then it's probably low carbon. The breaking test with a hammer is more reliable in my opinion.
If you quench the steel and it still bends then it's useless for knives, it has to be able to create martensite structure.
Hope this helps.
 
Londinium Armoury said:
Was it a track pin fron the actual tank you used? I have no idea what steel they are made from, do you know if they are high carbon steel or not? if you have some material left over do some tests on it. You can do a quench and snap test, this one is common for people who use old reclaimed steel, just quench it (don't temper) then get a hammer and try to whack a chunk off, if it shatters and breaks off clean then it has enough carbon to make a knife. Second test is get an angle grinder or something similar and look at the type of sparks that come off of it.
If the sparks "explode" like little fireworks and stream off into multiple directions then that indicates high carbon content. If you just get fine streams with no mini explosions then it's probably low carbon. The breaking test with a hammer is more reliable in my opinion.
If you quench the steel and it still bends then it's useless for knives, it has to be able to create martensite structure.
Hope this helps.
Click to expand...

I think it cant be by material because how i said, i made lot of knifes from this material but on none of them this happened, all knifes are very high quality.. but everyone can make mistake so its maybe some bad made piece. Its high carbon steel. Do you think i can save it somehow? I mean, to make it stronger? Because i really dont know what can be wrong... i made all same as i made every knife before.
 
Kellny said:
I think it cant be by material because how i said, i made lot of knifes from this material but on none of them this happened, all knifes are very high quality.. but everyone can make mistake so its maybe some bad made piece. Its high carbon steel. Do you think i can save it somehow? I mean, to make it stronger? Because i really dont know what can be wrong... i made all same as i made every knife before.
Click to expand...

Oh okay, I understand now, so the other knives you made were hard, and this one is the only failed one. Sure you can fix it, as long as you can keep heating it up you can keep re forging it and keep re doing the heat treatment unlimited times. Steel doesn't become ruined, everytime you heat it up past critical the steel matrix will go into solution and be reformed again and again.
Just start over and do the heat treatment again, there's no limit to the number of times you can anneal it, thermal cycle it, quench it and temper it.
You probably just over tempered it, or didn't hit high enough temp when you quenched it that's all, just start the heat treatment over again and it should be fine.
 
Londinium Armoury said:
Oh okay, I understand now, so the other knives you made were hard, and this one is the only failed one. Sure you can fix it, as long as you can keep heating it up you can keep re forging it and keep re doing the heat treatment unlimited times. Steel doesn't become ruined, everytime you heat it up past critical the steel matrix will go into solution and be reformed again and again.
Just start over and do the heat treatment again, there's no limit to the number of times you can anneal it, thermal cycle it, quench it and temper it.
You probably just over tempered it, or didn't hit high enough temp when you quenched it that's all, just start the heat treatment over again and it should be fine.
Click to expand...

Okay, im going to do it again so i will write you if it was successful or not. But i hope it will because of all hours on that knife.
 
vw8pLvk
t2zcShH

So we made it, i think its because i was heating it up in oven what have gas tube (i hope you know what i mean). Now when i did it with coil its hard and like every normal knife. So yakut knifes heat up before hardering just in hearth?

if the images wont upload here:
https://ibb.co/vw8pLvk
https://ibb.co/t2zcShH
Thank you for helping me.
 
Kellny said:
vw8pLvk
t2zcShH

So we made it, i think its because i was heating it up in oven what have gas tube (i hope you know what i mean). Now when i did it with coil its hard and like every normal knife. So yakut knifes heat up before hardering just in hearth?

if the images wont upload here:
https://ibb.co/vw8pLvk
https://ibb.co/t2zcShH
Thank you for helping me.
Click to expand...

Looking good, I like the second one a lot. No problem glad it worked out well.
 
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