1095 Won't Harden?!?

John mc c said:
Or it's not 1095
Click to expand...
Even mild steel will harden a good bit in a water quench. You have to get lower than 1018 to not harden enough to break it in a vise bend. Try this with a piece of hardware store welding steel to prove it to yourself. Common A36 steel will harden enough to skate a file in a water quench.

Larrin said:
Maybe I missed it in the thread, but how are you determining that they aren't hardening?
Click to expand...
He said he could file a big notch in the edge.

It has been my experience that even severely over-cycled 1095 steel will harden in a water quench.
 
Joshua Fisher said:
Not sure if this would help but perhaps heat the blades up to 1600-1700 then place them in vermiculite over night to try to anneal them then start over. It seems odd to me that they would suggest normalizing cycles to be the issue but it also seems like maybe you are doing too many cycles, in my experience 3 cycles of descending heat seems to work just fine but perhaps someone else can jump in. Another thought is perhaps do a high temp cycle as if you were forging the steel, so 1800-1900 without a soak time then start descending cycles from there, if you have more steel from the same bar perhaps cut off 4–5 coupons and create a baseline of what works and what doesn’t. As far as not being 1095 try spark testing it, if it sparks good then it gives you an idea it’s high carbon steel then try dipping a section in water, if it rusts Very rapidly then it’s not stainless. Just about any high carbon steel quenched in water from 1500-1600 degrees should harden. It doesn’t mean that’s the ideal heat treat for the steel or what type of high carbon steel it is but atleast you know it’s not mild or stainless steel.
Click to expand...
Thanks man, I’ll give that a try. I had them cross reference my order with the batch of steel and they are certain it’s 1095
 
Last edited:
Willie71 said:
That is too many cycles. Once you get past three, you can be refining the grain so much that you cannot get past the pearlite nose, no matter how fast your quench is.

Normalizing is the first cycle. The rest are grain refinement cycles.

Contact me at wjkrywko at gmail dot com, and I will give you my address to send me a sample. I’ll try my protocol and see if it hardens.
Click to expand...
Thanks man. I’m going to give a couple more things a try but if I’m still having issues I’ll hit you up. Do you think that re annealing and ht again I could save these blades?
 
milkbaby said:
New kiln? Don't forget to try hardening a known good steel sample in it to make sure that's not your problem!
Click to expand...
I have successfully hardened a couple knives in it already. And they were actually from the same steel as one of these that I’m having problems with. The only thing I’m doing differently is the normalizing recipe and I suppose the knives are half the thickness but seems the issue is the normalizing.
 
Conor Jensen said:
I have successfully hardened a couple knives in it already. And they were actually from the same steel as one of these that I’m having problems with. The only thing I’m doing differently is the normalizing recipe and I suppose the knives are half the thickness but seems the issue is the normalizing.
Click to expand...
I have some of their current batch of 1095, I’ll heat treat a few coupons from it and see how they behave but I haven’t had issues with it so far, the ends are all painted yellow and each bar had the steel and size wrote on it. 3/32” stock. Sounds like it may be the normalizing, try a few samples one with not thermal cycles at all just critical then quench then one with 3 cycles then a 3rd with your current amount of cycles break all 3 to see the grain and check each for hardness and see what happens, if sample 1 and 2 both harden then you know it’s the issue with all the cycling, I’ll replicate these tests in my forge and see what results I get and will get back to you.
 
Joshua Fisher said:
I have some of their current batch of 1095, I’ll heat treat a few coupons from it and see how they behave but I haven’t had issues with it so far, the ends are all painted yellow and each bar had the steel and size wrote on it. 3/32” stock. Sounds like it may be the normalizing, try a few samples one with not thermal cycles at all just critical then quench then one with 3 cycles then a 3rd with your current amount of cycles break all 3 to see the grain and check each for hardness and see what happens, if sample 1 and 2 both harden then you know it’s the issue with all the cycling, I’ll replicate these tests in my forge and see what results I get and will get back to you.
Click to expand...
That would be awesome. I will try it, hopefully I can get to it today. I have some stock from about 5 or 6 yrs ago so I’ll try some of that too just for fun.
 
Conor Jensen said:
That would be awesome. I will try it, hopefully I can get to it today. I have some stock from about 5 or 6 yrs ago so I’ll try some of that too just for fun.
Click to expand...
So I heat treated some test coupons in between work in the shop like I suggested above, all three hardened and skated a 64rc chisel, test coupon 2 had the finest grain as far as i could tell with 3 thermal cycles Coupon 3 was close to the same but felt more brittle in the break test. Coupon one has the coarsest grain of the 3, not sure if that helps any or not, but the test pieces were from a current piece of 1095 from NJSB, all of the ends of my bars are painted yellow with the stock size and steel type on them. This may seem like a silly question but I assume you are agitating your blades during the quench to prevent a vapor jacket from forming? Not sure if that’s the issue but if you aren’t moving the blade there could be a chance it doesn’t cool evenly.
 
Also I took a video of the testing and looking at the grain if you want to see it email me your phone number at edgeknifeworks@gmail.com and I can send it, it’s 7 minutes long and I’m not sure how to post it here, I think the file size is too big
 
Conor Jensen said:
Thanks man. I’m going to give a couple more things a try but if I’m still having issues I’ll hit you up. Do you think that re annealing and ht again I could save these blades?
Click to expand...

Normalize at 1650f for 10 min, two thermal cycles, then heat treat as normal. Put them in foil if you have it to minimize decarb.
 
Joshua Fisher said:
This may be a overly simple thought but the curie point of 1095 is 1414 F, so set your kiln to 1400 and the blade should still be magnetic, bump it up to 1425 and it should be non magnetic, that tells you it’s within 10 degrees or less. You could probably safely assume it’s accurate on simple steels are that point. Correct me if I’m wrong.
Click to expand...
Great idea!
 
Joshua Fisher said:
So I heat treated some test coupons in between work in the shop like I suggested above, all three hardened and skated a 64rc chisel, test coupon 2 had the finest grain as far as i could tell with 3 thermal cycles Coupon 3 was close to the same but felt more brittle in the break test. Coupon one has the coarsest grain of the 3, not sure if that helps any or not, but the test pieces were from a current piece of 1095 from NJSB, all of the ends of my bars are painted yellow with the stock size and steel type on them. This may seem like a silly question but I assume you are agitating your blades during the quench to prevent a vapor jacket from forming? Not sure if that’s the issue but if you aren’t moving the blade there could be a chance it doesn’t cool evenly.
Click to expand...
Interesting, thanks so much for doing that! Im curious to do that same test after checking my kiln temps as you suggested. I do agitate them for that reason. What are you quenching with and what temp?
 
Conor Jensen said:
Interesting, thanks so much for doing that! Im curious to do that same test after checking my kiln temps as you suggested. I do agitate them for that reason. What are you quenching with and what temp?
Click to expand...
I use parks 50, 5 gallons, at room temp, it’s working range is 50-120 so I see no need to mess with it’s temp unless it’s not within that range. If your checking with a strong magnet my numbers were slightly high and Devin and Larrin pointed out it actually be comes non magnetic closer to 1370 but still worth testing to see if you set it to 1400 the blade should not stick to a magnet. I do all of my heat treating in a forge with no light and a strong magnet to create a baseline, After awhile you get used to what colors in your shop should look like. I’ve heat treated over 100 blades this way with consistent results.
 
Thanks for all your help everyone! After testing 4 different coupons at different temps and normalizing cycles all which hardened above 65 I figured out that the problem was not the steel, my kiln or my quench oil but the issue was in the extensive normalizing cycle that was recommended that I was trying. It came from a very reliable source so I'm not sure why it didn't work for me but at least I figured it out. Thanks again for all the good suggestions! :thumbsup:
 
Conor Jensen said:
Thanks for all your help everyone! After testing 4 different coupons at different temps and normalizing cycles all which hardened above 65 I figured out that the problem was not the steel, my kiln or my quench oil but the issue was in the extensive normalizing cycle that was recommended that I was trying. It came from a very reliable source so I'm not sure why it didn't work for me but at least I figured it out. Thanks again for all the good suggestions! :thumbsup:
Click to expand...

Once you get past three grain refinement cycles, you CAN reduce hardenability so much you don’t get past the pearlite nose, no matter how fast your quench is. You will often see a lot of carbide banding too, and a carbon depleted matrix. More is not always better.
 
Willie71 said:
Once you get past three grain refinement cycles, you CAN reduce hardenability so much you don’t get past the pearlite nose, no matter how fast your quench is. You will often see a lot of carbide banding too, and a carbon depleted matrix. More is not always better.
Click to expand...
What does carbon banding look like?
 
You must log in or register to reply here.
Back
Top