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Advice on HT damascus


Jaro Petrina

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Hello, I forged this blank sword blade with edges from DIN C45W  and the core mix is construction steel+saw blade (nickel steel, but not quite L6)  about 1:1.  This is for my friend, who is gonna finish is. Its well welded, everythink came alright, but he sent it to hardening service, the edges came out RC 50, but as whole its soft and bends (as a 6 mm flat blank).   When I have done it I honestly thought the hardening problem will be the other way around, that is - the core will end up too hard as the saw steel hardens like for no reason, but its the other way around.  I honestly think, they botched it.  Now I am going to do it myself. What do you think. It should be at least bit springy I think.  I would quench this from about 860 C in hot oil and not temper too much. (20 mint at 180 C)

 

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DIN C45W is basically 1043/1045.  As such, the maximum hardness, depending on exact content, is going to be somewhere around 53 HRC or so as quenched.  Therefore it is entirely possible that they got it about as hard as they were able and had minimal drop in hardness with temper.  I would definitely recommend not using that alloy for edge steel. 

 

In general, I would recommend tempering cooler for longer over hotter and shorter.  I don't think 20 min at 180 C is going to do much for you.  But then again, I don't think much is needed.  Even still, I would say 150-160C for an hour would be better.  

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50RC is all I would want from edge. My question is why havent the core hardened at all, when the sawblades I use go martensitic like nothing. I think they overtempered it. Thanks for advice on the tempering,

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7 hours ago, Jaro Petrina said:

My question is why havent the core hardened at all, when the sawblades I use go martensitic like nothing.

Probably because you mixed it with construction steel that doesn't harden at all.  

 

7 hours ago, Jaro Petrina said:

50RC is all I would want from edge.

I would definitely recommend getting quite a bit harder and tempering back more.  Steel that has been tempered back from 60 HRC to 50HRC is going to outperform steel that went from 53 HRC to 50 HRC.  

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On 7/6/2022 at 6:15 PM, Jerrod Miller said:

Steel that has been tempered back from 60 HRC to 50HRC is going to outperform steel that went from 53 HRC to 50 HRC

I suspect the answer is going to go over my head but why is this Jerrod?

"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos qui libertate donati nescimus quid constat

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10 hours ago, Charles dP said:

I suspect the answer is going to go over my head but why is this Jerrod?

There is a lot going on, but I'll try to give the highlights.  I should clarify first, though, it isn't going to be an insane difference in performance.  Just a small difference.  

 

First thing to note is that tempered martensite is pretty good stuff.  But not all martensite is the same hardness.  More carbon in the martensite will make a harder martensite (and other elements have effects as well).  So a fully martensitic structure at 0.75 %C will not be as hard as a fully martensitic structure with 0.90 %C (all else being equal).  When we talk about steels that do not get very hard there is often more to it than a softer form of martensite:  mixed microstructures.  When you have a blend of martensite and pearlite or retained austenite you have a blend of performance.  More to the point though, is that the blend is not as readily controlled.  You get much more repeatable results when you go fully martensitic and temper it back more than when you are trying for "max hardness I can get out of this alloy".  When you look at the literature for different alloys you will see the ones that easily go fully martensitic have a fairly narrow hardness range (e.g. 60-62 HRC), whereas those with a mixed structure are going to be a bit wider (e.g. 54-60 HRC).  

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Not as painful as I thought. Thanks for the explanation and taking it easy on me ;) 

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"The way we win matters" (Ender Wiggins) Orson Scott Card

 

Nos qui libertate donati nescimus quid constat

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