1095 Quenching Liquid Questions

S

Smith Celton

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Oct 3, 2016
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Me and my friend have just recently created a foundry for melting metal. We put in an old mild steel knife I used to practice on, and it glowed orange/dark yellow. So I want to take a crack at making knives. The foundry gets around 1,700 to 2,000F, and I might get some 1095 HC for some amature knife making. The only thing is what do I use to quench it? I've seen you can use water, oil, or brine, but for me (even though you can use olive oil) oil for me of any type is going to be a hassle. I want to water quench it, but I've seen people say it has a high chance of cracking. Is oil better? So should I push through and get oil (and if so what type?), or use water and see how it goes. I have never worked with "real" steel for knives, just galvanized and mild.


Thanks,
Celton
 
I think you might mean a forge instead of foundry. 1700 to 2000 won't melt steel. That range might be a bit on the low side, but one of the experienced forgers would need to talk about that. 1400 to 1500 is all you need to harden most carbon steels. The most economical for hobby type work is brine. I've water quenched some very simple knives in 1095 (kiridashi shape) but most knives are a little more complicated. If it's something you like and keep doing, some good quench oil wouldn't hurt.
 
I might be misunderstanding, but you say you have worked with galvanized steel.
Make sure to educate yourself on that front - heating galvanized steel releases toxic zinc oxide, which CAN KILL YOU. See https://en.wikipedia.org/wiki/Metal_fume_fever

Regarding quench, water alone has been too aggressive in my experience for quenching - it can be good for some items like strikers for firestarting, but it has cracked a few blades.
 
If you need the speed of water/brine (don't have parks 50 or DT-48) then 3 seconds in brine, then finish quench in heated canola oil. It's the last part of the conversion that is more likely to crack the blade. Remove all stress risers, normalize and steppes relieve the steel befor heat treat. Temper immediately out of quench.
 
FunkCoaster said:
I might be misunderstanding, but you say you have worked with galvanized steel.
Make sure to educate yourself on that front - heating galvanized steel releases toxic zinc oxide, which CAN KILL YOU. See https://en.wikipedia.org/wiki/Metal_fume_fever

Regarding quench, water alone has been too aggressive in my experience for quenching - it can be good for some items like strikers for firestarting, but it has cracked a few blades.
Click to expand...

Just to keep inaccurate info from getting passed on:
Metal fume fever is not the same as zinc poisoning. You will not get zinc poisoning from zinc oxide. Metal fume fever is like flu, and causes nausea and weakness. You get fresh air, drink some milk, get a good nights sleep, and you will be fine in a day or two. Zinc poisoning is very rare in humans. If you read the wiki you posted, you would see that it says the same.


This has been discussed regularly. The myth that galvanized metal will cause death if heated is just plain false. That wives tale really got spread around after Paw-paw Wilson died from having pneumonia/flu and working in a closed up shop breathing metal fumes with cadmium and other bad things. Her wore no respirator and the shop had no ventilation. He damaged his lungs so severely he drown in the fluid leaking out of them. He also was burning off the plating and melting brass, not galvanized.
 
Which is why I do not work with galvanized steel anymore. I had never heat treated it, and when I worked with it, it was before I knew what heat treating was.
 
Willie71 said:
If you need the speed of water/brine (don't have parks 50 or DT-48) then 3 seconds in brine, then finish quench in heated canola oil. It's the last part of the conversion that is more likely to crack the blade. Remove all stress risers, normalize and steppes relieve the steel befor heat treat. Temper immediately out of quench.
Click to expand...

Just what I was looking for!

I presume I should be moving the blade around, etc.. for both steps (especially the brine - make sure I shed the steam jacket as effectively as possible during those 3 seconds?)
 
Steve98 said:
Just what I was looking for!

I presume I should be moving the blade around, etc.. for both steps (especially the brine - make sure I shed the steam jacket as effectively as possible during those 3 seconds?)
Click to expand...


Up and down or a slicing motion, not side to side. :D
 
The reason yaki-ire is done in a horizontal trough is that the slicing motion becomes part of the quench. In a brine quench of high carbon simple steels, there is less than one second for the drop across the pearlite nose, so all that is going to happen at the edge happens as the blade enters the liquid and moves downward. Even with a fast oil, a horizontal quench is more beneficial than a vertical quench. It is the simplicity and smaller footprint of a vertical quench tank that makes it more popular.

The best motion to gain cooling rate and have minimal warp is an edge first motion. This keeps the edge meeting unheated liquid not shielded by a steam jacket. Once the limits of the horizontal tank depth are met, reverse the stroke and lift the blade in the same plane. In yaki ire, the blade is often lifted from the tank for a few seconds to allow the hamon to bleed down toward the edge before it is lowered into the tank again to stop the auto-tempering.

With a vertical tank, the quench is minutely slower, so the blade should be moved back and forth in a cutting motion ( edge to spine plane). This requires a tank with sufficient width, which is why a vertical tank should be at least three to four times the blade width.

In a narrow vertical tank, the blade can be moved up and down, but this is the slowest quench of the three methods. It is just moving the blade up and down the steam jacket in a narrow column of very hot oil. It is better than holding it still, but not nearly as good as a cutting motion in a wider tank.
 
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