Water quenching?

M

MSCantrell

Knifemaker / Craftsman / Service Provider
Joined
Mar 12, 2005
Messages
1,213
So with all the recent threads on quench media, I started wondering about good old fashioned water.

I've quenched about a dozen blades in water, interrupted quenching each time. I cracked one (but it was a strange one- didn't crack in the quench, but later in the tempering).

Here's what I'm curious about. We all know that water quenching is dangerous, liable to break your blades. But if the blade survives, can you be pretty confident that the hardening went right? Assuming it skates a file, that is?

Or even with interrupted quenching in water, are you subject to the same metallurgical bogeymen, "fine pearlite" and "retained austenite"?

Or to put it a different way, water can clearly be too fast, so does that mean it can't be too slow?

Thanks,
Mike
 
Yes the same stuff happens but at a faster rate. If water is too slow then use brine ! The rule is to match the quench to the steel. You want a quench fast enough to get the proper transformations but not any faster.Faster would create excessive stresses and risk cracking.
 
I avoid critiquing water, or even discussing it all that much as it is a quenchant and one that set speed standards by which we measure others (e.g. the “H” factor scale) however I don’t use it because my timid heart finds the risk factor too high for my liking. I look at steel prices and the money I need to make and find the loss rate risk too high for sound business sense. But enough as to why I don’t usually discuss water, instead I should say why I decided to comment now.

Water has a huge vapor jacket! Most of your distortion issues are not due to cooling too fast but instead by cooling unevenly due to smaller sections plunging into other phases before the others can catch up, but even worse are the patchy areas unable to cool due to an insulating blanket of steam. In the area of the curve that you want to be the fastest to avoid pearlite you have the highest amount of vapor covering the steel and keeping it from cooling, water makes tons of vapor at 212F, that is much quicker than most other quenchants. Rather than speeding conduction up, adding the brine interferes with the stability of the vapor jacket causing it to collapse sooner and bringing more liquid into direct contact with the steel.

On the bottom end of the curve the blade is about to be subjected to huge stresses as it passes Ms, the more gentle the cooling here the better, water is the reverse, slow up top and screaming fast at the bottom. So it can set up all kinds of opportunity for distortion and cracking up top and then insure that they can happen at the bottom. This is why water quenching is for folks who are much more skilled and adventurous than my timid heart.;)
 
One aspect often overlooked in the quest to master water quenching as being the "ORIGINAL" quench is that the "original" steels were not the same as we are using. Most blacksmiths,prior to 1900, were using steels of much lower carbon content, and few alloying elements. 1050 water quenches a lot better than 1095. Some steel tools (including knives) were not much more than .30 carbon.

That, and the fact that they had learned the hard way to not overheat steel that will be water quenched.

I can see it in my head:
The smith is alone at the forge. His coal forge being gently pumped.....the smithy darkened....the blade run in and out of the coals to get even heating.....a skilled eye to know when it is at the desired temperature.....a smooth ,not rushed ,quench into the tub.
The smith is alone in the forge.....no one will ever know about the blades he broke.
Stacy
 
OK, SS, that's great!

But...

is there any sort of record that tells us what ratio of blades in medieval japan were junked due to cracking in the quench vs those that survived to become swords?
 
How long ago was magnetism known about... studied... played with? Was it after electricity?

Mike

Edit: Answering ones own questions... there by creating other questions...
The second link is from the first link... bottom of page
http://en.wikipedia.org/wiki/Lodestone
http://www.phy6.org/earthmag/lodeston.htm

So, when did knife/sword makers (other HT'ers) start using magnets?

2nd Edit: Should have said... in the 2nd link, towards the bottom, there is a reference to blades becoming magnetized by heating and cooling. I have no idea what and of that does or does not infer for dates of knowlege that may have helped HT control... less cracking... precise hardening... ???
 
Last edited:
Thanks for the good info guys. I have to admit it still tempts me, but that's probably because I haven't experienced the (reputed) joys of Parks 50.



Mike Krall, Ancient Greeks knew about magnets ("magnet" is a greek word), for what that's worth. Edit: (Actually, a quick googling indicates that the person to write about magnets was Thales about 580 BC, and also the Chinese had compasses in the first century AD.)
 
I'm going to copy this and hang in on the shop wall :D


One customer has sent me some questions for the smith. Then I asked him the questions.
--------------------------------------------------
An interview to the smith at his forge.
Question; How much carbon content does the blade steel have?
Answer; I don't know, because I have no carbon-counter. Probably the carbon content is uneven throughout the blade, because it is handmade.
Q; What is the temperature of the blade at yakiire?
A; I don't know. I see only the colour of the steel in the fire. The temperature may be different everywhere on the blade. I can't make an even colour throughout the blade.
Q; Why does the hamon become so irregular?
A; Please ask steel. I just use it.
---------------------------------------------------
I have found that the smith is just a practical craftsman.
Click to expand...
 
Dan Zawacki said:
OK, SS, that's great!

But...

is there any sort of record that tells us what ratio of blades in medieval japan were junked due to cracking in the quench vs those that survived to become swords?
Click to expand...

I was responding to this;

"One aspect often overlooked in the quest to master water quenching as being the "ORIGINAL" quench is that the "original" steels were not the same as we are using. Most blacksmiths,prior to 1900, were using steels of much lower carbon content, and few alloying elements. 1050 water quenches a lot better than 1095. Some steel tools (including knives) were not much more than .30 carbon

I don't know the failure rate on swords, I would Imagine Rick Barret, or Walter Sorrell would be able to answer that.
From water quenching 1095, I figure I do great with 1 out of 5 failure rate.
I have some White #2 that I'm going to start working with and see how it goes.

as far as "failure rate back in the day" I'm not sure anyone will ever know:(
Steel was so expencive to come by I garuntee they recycled it.
 
So far I have found cracking and warping (using water) depends on #1 if you have overheated or heated unevenly (I use a pyrometer in my forge to avoid overheating now),#2 if the edge is thinner than a nickel (approx) and #3 if you have properly allowed your clay to dry (if using clay). I have found the clay will boil off in spots if it's not dry and I don't believe wrapping in wire solves this either. There could still be blotches of clay that have lifted off the steel where you can't visibly see it. That's been my experience so far. I have been doing interrupted quenches with my 1095. I'm just not brave enough to leave it in there until it's completely cooled. I go in for 5 seconds out for 5 seconds back in until it stops sizzling then into the oven for a temper. I tested the blade and it performed very well. So far it's been working for me. I'm sure through experience I may change my methods...but so far this has worked the best for me. With water quenching I would expect a bit of warpage because it's such a volatile practice. :thumbup:

My 2 cents.

Mike
 
SShepherd said:
I don't know the failure rate on swords, I would Imagine Rick Barret, or Walter Sorrell would be able to answer that.
From water quenching 1095, I figure I do great with 1 out of 5 failure rate.
I have some White #2 that I'm going to start working with and see how it goes.
Click to expand...

Rick uses park's now and Walter uses a water/oil combination.
 
Robert was telling me about an article over on swordforum somewhere in the kuhkri forum where a guy from sheffeild was telling about how they used to use 1095 and whale oil for all the swords.
 
I have a small skinner in 1095 going to the fires tomorrow. I wonder if I can summon the courage to go water, or if I should use the 10w30 again. Any ideas? The edge is about a penny's thickness, no sharp corners.
 
well I'm 4 good 1095 blades out of the last 7 I did with water.

I take a 5 gallon bucket...1/2 hot, 1/2 cold water..then I do what I mentioned above. 4/7 isn't the greatest but it's better then 50% of the time and from what I've heard that's not bad.... your call though. I have to say though the hamon with water beats any I've gotten with canola oil...and yes I realize canola oil isn't designed for quenching 1095 but it's what I had used before. To me the results of a successful water quench are totally worth it.

Good Luck!!:thumbup:

I know how frustrating cracking blades is. It drives me nuts when I show someone a nice hamon and they look and say "ya it's nice" and don't pay too much attention to that particular aspect of the knife. They have no idea how much work it takes sometimes to produce a knife like that!

mike
 
I've never done a hamon- is it from letting the edge have first shot at the water, then lowering it all in? What's the etch, ferric chloride?
 
You must log in or register to reply here.
Back
Top