How do I heat treat and temper 1095 steel?

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fishinhook

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Hi guys, I'm new to knifemaking. I've grinded some knives out of 1095 steel and now need to heat treat and temper the blades. I was wondering if someone would be so kind as to tell me in terms that I can understand how to do this. BTW, I will be using a knife oven. Unfortunately my search button is giving me trouble and I can't look this stuff up on the forum. Thank you in advance, fishinhook.
 
Really a loaded question, as the views range from what will work, work wonderfully, to all kinds of ideas on what is the accepted 'best' method.

To search the site from google, type your search here,,,, if your a coffee kind of guy, start a fresh pot, you will be parked for a while!

LINK​
 
1: heat the knife up to Aus Temp.

2: Quench the knife in a fast enough medium to reach Martensite Start without forming pearlite.

3: let cool to below Martensite Finish

4: Temper

Not trying to be snyde, there are a large number of variables that will define how to advise you to perform each of these steps
 
Maybe a little more information to help
1: heat the knife up to Aus Temp. You will need a pretty good torch or some why to direct the heat, about 1500 F, you can heat directly with a oxy acetlyene torch. Check temp to just non-magneting.

2: Quench the knife in a fast enough medium to reach Martensite Start without forming pearlite. Hear is the tricky part, you have to get the blade cool in about 1 second, have your quench medium usually a light oil right next to where you heat and plunge the blade in. Some use water but cracking may be an issue, others use brine (salty water).

You can check your blade by running a file across the edge, it it skids you have something harder than you started. If if bites it needs to be done again.


3: let cool to below Martensite Finish cool to about 125f

4: Temper put in oven at 400f for about two hours, cool to room temperature and do again.
here is a helpful link, good luck

http://www.geocities.com/son_of_bluegrass/heattreat.html
 
Maybe a little more information to help
1: heat the knife up to Aus Temp. You will need a pretty good torch or some way to direct the heat, about 1500 F, you can heat directly with a oxy aclyene torch. Propane torch in open air will only heat a small blade. Check temp to just non-magnetic.

2: Quench the knife in a fast enough medium to reach Martensite Start without forming pearlite. Hear is the tricky part, you have to get the blade cool in about 1 second, have your quench medium usually a light oil right next to where you heat and plunge the blade in. Some use water but cracking may be an issue, others use brine (salty water).

You can check your blade by running a file across the edge, it it skids you have something harder than you started. If if bites it needs to be done again.


3: let cool to below Martensite Finish cool to about 125f

4: Temper put in oven at 400f for about two hours, cool to room temperature and do again.
here is a helpful link, good luck

http://www.geocities.com/son_of_bluegrass/heattreat.html
 
There really shouldn't be that many different answers since the heat treatment is pretty straight forward.

Heat evenly to 1475F for 10 minutes then immediately quench in fast oil (fast enough to cool the steel through the 1200F-1000F in less than .5 seconds). For simplicity sake cool to at least 150F before tempering. This should get you a full 65HRC hardness with no problem, tempering should be done without delay. Tempering should be for 2 hours at the temperature to reach the desired final hardness. 400F to 450F is a good range for knife blades.
 
stupid question.....can you really heat a piece of steel to 1500 degrees and hold it there for ten minutes with a torch?....tha doesn't seem like a great solution....i'm not dissing anyone's methods...just wanna learn....ryan
 
ryan9977 said:
stupid question.....can you really heat a piece of steel to 1500 degrees and hold it there for ten minutes with a torch?....tha doesn't seem like a great solution....i'm not dissing anyone's methods...just wanna learn....ryan
Click to expand...

Anyone who has tried, and monitored their efforts with a reliable pyrometer (temp gun) will tell you NO! A couple mins seems like an eternity.. That's why I invested in an oven.:thumbup:
Matt Doyle
 
You can call me sometime and I will be happy to go over it with you. The kind of setup there will play a big part in the making of the knife. Be safe out there. :thumbup:
 
You shouldn't soak your 1095 at critical for 10 mins. It is a simple steel and if you soak it you sure will ruin this steel... You only check it with a magnet and leave the blade at forge (or under torch) only a minute or so to equalize... Then quickly quench...

look at this page: http://ajh-knives.com/metals.html
 
What happens to ruin the steel by soaking at crit? If you soak above crit you will get grain growth, which tends to happen very quickly any time you overheat 1095. The point here is that heat treating 1095 with a torch isn't optimal, you can't hold it at temp for 10 min.
 
galadduin said:
You shouldn't soak your 1095 at critical for 10 mins. It is a simple steel and if you soak it you sure will ruin this steel... You only check it with a magnet and leave the blade at forge (or under torch) only a minute or so to equalize... Then quickly quench...

look at this page: http://ajh-knives.com/metals.html
Click to expand...

Soaking a hypereutectoid steel like 1095 is the only way to get enough carbon in solution for optimal hardness in the quench. Soaking at 1475 for 10 minutes will cause no appreciable grain growth (that is assuming the grain was fine from previous thermal treatments).
 
Grain growth is much more a function of temperature than time . Forget the torch.
 
Kevin R. Cashen said:
There really shouldn't be that many different answers since the heat treatment is pretty straight forward.

Heat evenly to 1475F for 10 minutes then immediately quench in fast oil (fast enough to cool the steel through the 1200F-1000F in less than .5 seconds). For simplicity sake cool to at least 150F before tempering. This should get you a full 65HRC hardness with no problem, tempering should be done without delay. Tempering should be for 2 hours at the temperature to reach the desired final hardness. 400F to 450F is a good range for knife blades.
Click to expand...

Kevin you said tempering should be for 2 hours at the temperature to reach the the desired final hardness. Do you have a break down of the temps. Like if I want HRC 61, what temp would I need to be at. Also is there a book or chart for the different steels that a dummy would be able to read and understand. Thanks.
 
I would give you a full breakdown but I am typing this reply in a hotel in Cave City KY as tomorrow I am taking my kids spelunking:). There really is no substitute for the ASM Heat Treater's guide for this type of information. It will all depend upon how much carbon is put into solution. With a really good soak you will need much higher temperatures to soften in tempering. Depending on how you did things 420F could get you 61HRC or 440F could be more like it.

While I wouldn't want to see Galadduin piled on too heavy, I am glad to see the number of folks who thoroughly understand that without exceeding Accm there can be no grain growth, this is one of the reasons that the recommended temps are lower than 1500F, so that one can soak as long as they like if they have control over the temp.
 
Kevin, I have to say, your patience is astounding. You've answered this exact same question about 5 times in the last couple of months (at least once for me :D) and you never bag on noobs for asking it. You're ridiculously generous with your time and your knowledge and I want to say thanks. Really. Thank you.
-Gavin "Still a Noob Myself" Rondeau
 
WadeH said:
Kevin you said tempering should be for 2 hours at the temperature to reach the the desired final hardness. Do you have a break down of the temps. Like if I want HRC 61, what temp would I need to be at. Also is there a book or chart for the different steels that a dummy would be able to read and understand. Thanks.
Click to expand...

Here, scroll down a bit. Link 61 would be 400F, 59, 500F.
 
I'm about to attempt my first blade, so I'm trying to research as much as possible so I don't ruin it too much. I have seen some tempering processes that use a sub zero quench with dry ice and a solvent like acetone. Is that applicable to 1090, or is that a special process for a particular metallurgy?
 
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