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Water quench vs oil quench hardness


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So i failed in my quest to differentially harden my en45 katana, although I did gain the right amount of sori I was hoping for. To cut a long story short, I finally ended up through hardening the blade with a water quench. 

I spoke to a local knife maker who told me that I wouldn't get full hardness with this steel in a water quench - if anything, due to the significantly faster quench, I was expecting perhaps slightly higher hardness with an increased risk of cracking? I guess I could get the blade hardness tested once life returns to normal, but in general, when quenching a steel in water, does this reduce the as quenched hardness? Thanks. 

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Using en45 you will get higher hardness in water than oil. Honestly I think you will almost always get a higher hardness using water over oil.

Edited by Jeremy Blohm
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EN45 is equivalent to our 9260.  The low carbon content and the silicon in it gives it some toughness.  Because of that you'll find that alloy being used in swords and big choppers, if you can find it[i/].  There was only one outlet for 9260 here in the states and they stopped carrying it a few years ago.  Now it's unavailable here unless you want to buy a couple of tons at a time.

 

Doug

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2 hours ago, Jeremy Blohm said:

Using en45 you will get higher hardness in water than oil. Honestly I think you will almost always get a higher hardness using water over oil.

I have serious doubt about this statement just by looking at the alloy content. Some Cr, some Mo, some Ni and manganese of 0.6 to 1... 

To me it looks like a steel that will get full hardness in 11 secs oil. 

Screenshot_20200510-190225~2.png

Edited by Joël Mercier
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Hmm.. Interesting... Well what I can say is that this steel does NOT heat treat and behave like 5160. The final performance I think might be similar. When I was even more of a newbie, I noticed that 5160 would slightly air harden with overly aggressive grinding. En45 doesn't seem to have this problem. This as well as the fact that it seems to survive a water quench without too much hassle, as well as that some are able to get a (fairly dull) hamon with en45, leads me to think it is much more shallow hardening than for eg 5160.

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Another question - I have noticed that a successful quench always gives a very characteristic grey colour- has anyone else noticed this? 

 

Finally, does anyone know which of the bohler tool steels are shallow hardening? Steels like 1060, 1095 aren't available in South Africa. The nearest thing I have been able to find is en9 (basically 1055).

The goal is to create a hamon. Perhaps I should just persist with en45..The only thing I don't personally like about it is the very high austenisation temperature. Maybe it is possible to get an active hamon with this steel? 

Edited by Gareth Barry
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I find that if the blade has been ground clean before hardening, that the black scale almost always pops off or becomes so loose it can be cleaned off with a rag after the quench. It also gives you a good indicator of where the blade has been hardened and where not. I always aim for that demarcation to be half an inch to an inch forward of the tang-blade junction.

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EN45 is odd stuff.  It does take a faint hamon, which it should not because of the chromium and manganese levels.  The extremely high silicon makes it tougher than most other speing steels, and probably has some effect on depth of hardening.  I like it, but as Doug said you can't get it in the US.  

You said you can get Bohler steels?  How about Sandvik? 

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38 minutes ago, Jim Kehler said:

As far as I was taught; it's either hardened or not, what quench medium you use (oil, air ,water, brine, caustic soda) depends on hardenability .

Not necessarily.  If your quenchant and everything is just right/wrong then you can get less than 100% martensite.  For all practical purposes, 100% martensite is equally hard regardless of how it is formed.  But if your procedure only gets you 75% martensite, whether the remaining 25% is bainite, retained austenite, or pearlite, then you will certainly see a difference in hardness.  

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2 hours ago, Gareth Barry said:

Thanks Alan

I'll have a look at Sandvik in terms of local availability. 

Which of the Sandvik steels would you recommend for getting an active hamon, ie shallow hardening / water quench steels+

 

26c3 from Sandvik has good recommendations.  

 

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26c3 is made by Voestalpine, a Bohler/Uddeholm specialty division. I really love that steel btw, but it would make a very poor sword steel. It has way too much carbon!

 

Sandvik makes 20C, which is a cleaner version of 1095. It would be a better choice, but it still has more carbon than necessary.

Edited by Joël Mercier
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