1095, What happened?

Joined
Jul 17, 2006
Messages
772
Hey there, just got done making a knife and breaking a knife. Started to heat up, ran out of propane, ran to hardware store, got more propane, heated blade to non magnetic, quenched in 140 degree oil, tempered in oven for 2 hours at 325, air cooled, minor warpage, tried to straighten, SNAP!!!, what happened? I had just done one exactly like it and it was fine, same warp, straightened it and no snap and it came out great. Was it because I ran out of propane and didn't anneal after that and start over?:confused:
 
I'll take a guess.......

1095 is a tricky steel for me. If I don't anneal it "correctly" it won't heat treat properly. I also temper 3 times at 375* AND allow it to air cool each time. You may have your heat too high, or your soak time too long. PLUS, sometimes they just break for like no reason! At least that's my experience.
 
First - 325 is way too low for anything but a hard temper in 1095. If you try to bent it at that temper, you will most always break it. Try bending a file...even a little bit.
Second, you should straighten any warps immediately upon quench. Quench 1095 and count to five ( If it isn't cooled below 900 by then it is not going to harden right anyway) and pull it out of the oil. It will be HOT and smoking. Check for warps,. If there are any, straighten at once. Slap it on the anvil and give it a couple of whacks with a hammer, or stick it in a vise and bent/twist all you need. It is very rubbery at this point. DO ALL STRAIGHTENING BEFORE IT GETS TO 400F. Once it drops below 400 the Austenite starts to convert to Martensite and is very brittle. Even after three tempers at 400F, 1095 doesn't like to bend. At 500F it becomes a spring.

If you made another similar blade and tempered it at 325F and could bend it.....I think you didn't hit the cooling curve properly. It should not have bent more than a tiny bit.

Breaking a few blades is the way we all learn with 1095, Usually at quench.
Stacy
 
I like 1095 for fillet knives. It makes a beaut. Tempered properly it has all the qualities a fish skinning knife should. 400/425 fh, its ductile, tough and
easy to sharpen. 325/350fh, its still mighty brittle. You have to temper where
the transformation to martensite takes place. In this case with 1095 it is the low to mid 400's. You know they are getting hard because they are snapping.
Just turn the heat up a little and you'll have it.

Fred
 
The good news is that the steel performed exactly as it should with such a low tempering temperature. I often get a really good idea of how a smith or maker is doing in his hardening operations by what his tempering temperatures are. Often I hear of smiths that are tempering larger chopping blades at less than 350F and not running into problems with brittleness. This is a dead give away that their hardening was much less than optimum. Properly soaked and quenched 1095 gets very hard indeed and takes some seriously high temperatures to lower the HRC. If it got fully hard one shouldn't expect to see much of any softening until you get between 375F and 400F, and that is just the beginning.
 
I temper 1095 for a filet knife at 400* 3 times. It will give a little, and hold an edge forever.

What's your take, Kevin?
 
Thanks everybody, I had the hardening/tempering recipe written on a post it note and lost it and was too lazy to look it up again and I thought I remembered it correctly, oops! I just found the post it note, it did say 375-400 degrees. The other one that didn't break was tempered at 375 twice. Thanks again.
 
It sounds like you got it into quenchant quickly enough. Maybe the snap-pop-and crack is a good indication for you. Hate to loose a blade though. Three twenty five F. is a pretty good snap temper range (NOT temperature to snap the blade but as in the term 'snap temper') and I wonder too why it snapped on you. A good or a couple good oven thermometers will help you keep your temper oven honest. My hat off to you for tackling the 1095; that's a tough one for us to HT properly. The torch helps you get it into quench quickly; exceptionally important for 1095.

rlinger
------
 
"My hat off to you for tackling the 1095; that's a tough one for us to HT properly. The torch helps you get it into quench quickly; exceptionally important for 1095."

I had heard that 1095 was one of the easier ones to work with, I guess not. I hate putting all that work into a blade and losing it! Oh well. I have a forge I used to heat it, I guess I made it sound like I used a torch.
 
It should be remembered that 1095 has been used as a blade steel for many, many years .It really isn't all that difficult to HT properly !..Always try to straighten at the tempering temperature not below !..If you were to look at my various posts you would find I mention 400 F for tempering . This is not just my idea but has been used in industry as a common tempering temperature .350 F sometimes is not satisfactory.
 
Perhaps I misunderstood, not uncommon for me. I thought I read torch and will go back and read your posting again. The 1095 is easy to work I suppose by comparison but not easy to properly heat treat relative to other simple carbon steels we use. Basically stated 1095 is very partial to super quick to quenchant. I can not do it as well as I think it should be done. My very best to quench is about 1 second. That is way late, in my opinion. Lots of makers may tell me I am full of it. I think I am not (on this, that is).

rlinger
------
 
1095 is a simple steel....basicly 99% iron and 1% carbon. It forges easily, takes a very sharp edge, is tough, and is cheap. The HT is well established. With the proper HT procedures (especially normalizing) it quenches well and gets quite hard. It does require a fast oil....or a water quench for the brave.
I call it a "Paint By Numbers" steel. The procedural format is all laid out for you - just do each step as proscribed ,and it will yield a known result.

As far as tempering temps go, (assuming a proper quench with full hardening) there is little drop in hardness until 500F. Assuming an as quenched hardness of HRC65, the hardness should be about HRC 61-62 with a 450F temper. I usually do 1095 at 425F. At 600F you will still get HRC 55-57

The ASM "Heat Treaters Guide" gives this info:
Procedures -
FORGE
NORMALIZE
ANNEAL
ROUGH MACHINE (grind)
SEMIFINISH MACHINE (shape bevels,drill holes,sand smooth,etc.)
AUSTENITIZE
QUENCH
TEMPER

forge at 2100F
normalize at 1570F
anneal at 1475F and cool at 50F/Hr
austenitize at 1475F
quench in oil (fast oil for knife blade thickness)
temper between 400F and 600F (for knife purposes)

1095 responds well to austempering ( referred to as ausquenching by some), with the quench being done in 600F salt and held at that temp for 2 hours. It forms Bainite (instead of Martensite) this way. (Tough and hard)

Stacy
 
I agree straighten right from the quench.
I push to 450 and as high as 600 depending on if it's a chopper or not..
all things depend on its use.. and just how hard you got it in the quench also.

Blub once you get in a comfort zone doing this it will be easy for you..

but watch the forge heat , using it, you'll need to read the steel :)
using a magnet only tells you it's with in ~100 degs of the right heat to quench, but also remember it will stay non magnetic at a much lower heat once you get it there, so you can be at a to low a heat and still be non magnetic. I hope this is understandable, Kevin and the others are much better at the typing and communicate thing :)
 
I quit using 1095 about the time I got my Rockwell tester, and switched to W2, so I don't really have much to say about 1095. But for W2, I temper at 475-500, and get a hardness of 60-61. I recently water quenched a sample of W2, and it was 67 Rc out of the quench. :eek: :D Great stuff.
 
I'm with Phillip on this one.

I made a lot of good knives with 1095 years ago but you just don't know what you get now days when you buy 1095.
 
About the only advantage 1095 has over W2 for the beginning forger or for grinders is that it comes in flat stock, whereas the W2 needs a lot of work forging it down.
 
Thanks for all the replies, I guess I need a pyrometer for the forge to be sure of the temps I'm using.
 
rlinger - my quench bucket around 6 inches away from the mouth of my furnace. I do a lot of 1095...and thin (1/8")....1 second (as you stated) is too long for my stuff...I've set things up so that I can consistently get it in there under 1 second. At about 1.5 seconds the edge is already darkening (as it shows during normalizing).


After quenching, I knock the clay off my blade, clean it quickly and stick it in a vice between two large aluminum plates. I rarely get warpage, ever.

I also temper at 400F for 2 hrs.


Took some broken blades to get where I am now....:(
 
The .8 seconds you have with 1095 is not the oven/forge to tank time. It is the quench temp (1475F) to 900F time. The steel will stay hot enough for any normal transfer time from oven to tank. The regular oil is not fast enough to cool the steel in .8 seconds or less. Water or fast oil is required.
Stacy
 
Back
Top