can 1095 steel lose its hardenability?

R

rjfm1972

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Jan 13, 2013
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As the post asks..... I have a blade I was working on and decided to treat it in my new forge. I may have waited too long to quench and it wasn't hardened 2/3rds of the way down the blade. So I treated it again, and the whole blade seemed to soften up, even with the fast quench. So I tried a third time, till the whole thing was non magnetic and heated evenly. Fast quench again (mcmaster carr fast quench oil) and now I can scratch this stuff with my hardness file marked 40RC. So I concede this blade is trashed.... but is this how this steel is? One chance to do it right? Keep in mind that I have done several blades with Hamons cut from the same plate of steel, and all have turned out well. This material was already in the annealed state before being worked and treated.
 
Grind it down a bit and test it again on fresh steel.

How long did you hold it at temp before quenching?
 
Yup, probably a good layer of soft decarb skin on it. Grind a good edge , taking it back a few hundredths. I bet it id sharp and hard there.
 
What sort of normalzation cycles did you run? It is possible to refine grain too much.... but as others have already stated, it is most likely a layer of decarb.
 
and if you only heated it to nonmagnetic you were about 50 degrees shy of being hot enough. you may have good steel under your decarb layer. Hardness files don't work very well since they only scratch the surface

-Page
 
Interesting....all the research I have done and I never read anything about a decarb layer. So This blade may still be good? Does a really thin coat of satanite prevent this from happening? Is this layer thin enough to hand sand out, or do I need to actually grind it out? Sorry, still so much to learn apparently. Also, am I supposed to hold it at temp for long? I didn't know 1095 needed that. I was just bringing it up to temp for a few minutes and then quenching. Please keep in mind, this is the exact same process I did with my blades I have produced nice Hamons on, and they were testing with the files between 55 and 60 (didn't scratch with the 55, but did slightly with the 60)rc. Rick, I didn't normalize because this was annealed material and was not forged, only ground. Do I need to normalize if its not forged?
 
rjfm1972 said:
Rick, I didn't normalize because this was annealed material and was not forged, only ground. Do I need to normalize if its not forged?
Click to expand...
I thermal cycle everything. If you are going to do your own heat treat, why would you leave a huge variable like that, unknown? Unless you have certs with temperatures, you have no idea about grain size or uniformity. That said, I wouldn't mess with PM steels prior to HT.
 
So, I decided to temper the blade before trying to take off the decarb layer. I noticed a slight bit of warpage and when it was nice and hot I went to straighten it. With almost no effort, snap! It had a small crack in it. I am 100% certain I got it too hot on the last heat treat because I thought I wasn't getting it hot enough. I will say this...the grain was VERY consistent, and very small. I think this heat treating is going to have an expensive learning curve. I have some 52100 and some CPM S30v I bought from Aldo that I really KNOW that I should send to get treated, but WANT to do myself. LOL. Don't worry though, I have plenty of 5160 to play with as well first. And I've had pretty good luck with that stuff so far.
 
How are you planning on heat treating S30v as it is apparent that you do not have any sort of temperature verification or control? That would be an expensive learning curve for sure. When starting out, I heat treated a bunch of O1 in a refractory brick forge. Some of it worked out, much of it wasn't optimal. The reason is that O1 needs a bit of a soak to maximize its potential, and I didn't have the means to control the temperature. I wanted to produce better work, and if I wanted to do it myself, I knew I needed control and consistency. So I built myself a PID controlled heat treating oven. It was a fun project and bridged the gap until I was able to buy a commercially built oven.

Temperature control is paramount when you start working with more complex steels. 1084 would be best if that was lacking.

--Nathan
 
My temp gauge goes up to 1950 degrees. I have had a little success playing around with the regulator and bringing it up to max temp and down to 1500 degrees and being able to hold the temp there. As I said though, I may cut and grind out several blades, play with one, and if successful, continue. I am sometimes a glutton for punishment. I AM going to try and learn this stuff, and figure if I can learn this, I should be able to learn to heat treat anything. My forge runs quite hot and will hold the 1900 degrees the S30V needs to soak at running at only 5-7 psi(hit 1900 at 7, started turning it down slightly to see if it would hold 1900 and it seems like it starts to go down at 5).
 
How hot a forge gets is to Heat Treating S30V ,as, how cold your freezer gets is to walking the dog ( You don't use the one for the other in either case).

S30V needs a complex HT done in a closed electric HT oven. After sealing the blade in a stainless foil packet, it has to be heated in a couple of exact steps to around 1950° and then held at that EXACT temperature for 30-45 minutes.........not going to happen in a forge. After the austenitization hold, the blade is hardened between two large aluminum plates. Then it is snap tempered and placed in liquid nitrogen for a few hours. After that it is tempered twice. Tempering should be done in a fairly controlled oven, but a good kitchen oven will work.
 
Looks like I'll be sending them out then.... Is there anyone who specializes in treating stainless steels?
 
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