1095 Cracked AGAIN!!!

[DaveRuhlig]

I know 1095 is supposed to be the "Newbies Steel" because of it's forgiving nature, ease of use, and price but it's frustrating the crap out of me! What am I doing wrong? First my process, then the pics. First I grind to about 220 grit leaving about a dimes width at the cutting edge. Heat to non magnetic in my mini blown forge - specifically heat to bright orange, take it out of the forge and test with magnet, put it back in for about 20 seconds, take it back out and quinch immediately (as fast as my hand can move about 16"). As soon as it's cool enough to touch I spray with wd-40 and scub some scale off with a scotchbright pad then directly into a preheated 400-425 degree oven for 1 hour. I should add my quinch tank sits on top of my toaster over and gets to about 100 degrees prior to quinch and is filled with a mixture of motor oil and olive oil.

On this particular knife I went through the process above, finished to 600 grit and etched. I didn't even notice the crack until after the etch which frustrated me more than anything else. All that work and I thought I was done with the blade and then I notice the crack!! I know there are a million recipes for 1095, but if you have one that works I'd like to hear about it. If you notice a flaw in my process I'd like to hear about that too. By the way the stock is 1/8th by 1.5".

Obviously it ruined, but since I spent so much time already I went ahead and put a simple wrap handle on it so I could beat the crap out of it around the shop and see what happens to the crack over time.

Here are the pics:

First, the completed knife - doesn't look too bad huh?


Now the crack - it's about an inch back from the tip, goes up about a half an inch and curls back towards the tip.


Thank for any input!
-Dave

[DaveRuhlig]

One more cropped look so you can see where the crack is:

[son_of_bluegras]

How did you decide on "bright orange" for the temperature color? Have you check that in some way, what about ambient light, if you work in a fairly bright shop then I can almost guarentee that was too hot; depending on your eyes and how you interpret colors, that may be too hot in a dark shop. I see the color as bright red/dull orange in a dark shop when I see the descalence that accompanies the change in the steel.
Did the tip get hotter then the rest, since you said the crack is near the tip, that is also a possibility.

ron

[wolf9416]

Hi Dave,I can only tell you what works for me-I heat my quenching oil to at least 140 derees.After it's been in the quench tank a while I take it out using a rag or pliers to hold it on the board(still to hot to handle)then scrub it down,wipe it off and put it in the oven.your problem may be in spraying it with the wd-40.you might want to invest in a thermometer like a bluing thermometer to see where you're at on the quenh heat.I've used a lot of 1095 and(knock on wood) never cracked one yet.I use canola oil all the time.it;s worked for me.hope this helps a little.Take care....T-wolf

[Whiskers]

A bright orange might have been a little too hot. I am not sure that that would cause a crack but it might have. Whiskers

[Kostoglotov]

Dave

You may be overheating the blade, especially the edge. If your forge can reach welding temps (assuming that it can w/ forced air), the additional soak may be pushing the steel up a significant amount. You may also be inducing stresses in the blade by having the edge hotter and thinner than the rest of the blade.

I'd get it to temp, try and get the blade to "equalize" temps across the section (Pull the blade out and let the color become equal across the entire blade) and then quench.

[Wade Holloway]

Dave where did you hear that 1095 was a beginners steel? I had always heard that 1084 was. In fact some of the stuff I have been reading has been about hard 1095 has been to get it heat treated right and consistant. As far as oil goes I have been told that you need a fast quench oil like parks 50 for a quenchent.

[WBE]

Wade is absolutely correct. I was going to ask the same question. 1095 is definately NOT a beginners steel, or easy to use without the proper equipment and knowledge. You did not mention normalizing. You MUST normalize 1095 to de-stress it, or you will get cracks. Forged, or ground. Your quench oil will not get it full hard. Acually no oil quench will, but Parks #50 will get it as close as possible using oil. Your quench oil needs to be around 130?, and some will heat to 140?, which I think a tad high, but I have not tried it. You are dealing with a hypereutectoid steel, meaning that it has more carbon in it , than will go into solution. This extra carbon needs a 5, to 10 minute soak at around 1475?/1500? to disperse evenly, then a very fast quench to lock that solution in place. Your best direction is to go to a steel like 1075/80/84, and forget 1095. A major problem with 1095, even when it doesn't crack, is that if not quenched fast enough you get hard pearlite, instead of good martensite, and a file will still skate over it like it was glass. You end up not knowing the acual condition of hardness you have, and if hard pearlite, it will not hold an edge as it should, or could. 1095 is also bad about carbon collecting in the grain boundaries, which causes weakness, and cracking. You will never get it it properly hard with the quench mix you are using. 1075/80/84 is almost foolproof in HTing, and will out perform 1095 that is not properly HTed, and come pretty close to 1095 that was HTed right. These steels have much more manganese in them than does 1095. Manganese prevents the majority of the problems found with 1095, and makes these others deeper hardening. If you cannot afford commercial oil, switch to canola, or mineral oil. Switch to the steels mentioned, and follow a better HT plan. With the alternate steels mentioned, a couple of shades of red above non-magnetic, with a couple minutes of soak will easily full harden it in most any thin oil, with little chance of cracking, but you still want to normalize first.

[ranger1]

Dave,
I am no expert but use 1080/1095 on about all my forged blades. I cracked allot of blades. Temp was the culprit. I purchased a Pid controller and thermocouple for about $80.00. Here are links to the parts http://auberins.com/index.php?main_p...ec337cb3646776
http://auberins.com/index.php?main_p...products_id=39
Once set up you can adjust air and fuel and hold temps within 25deg F.
Now I'll tell you my process.
I forge the blade. I then anneal the blade by heating to 1500 and letting air cool, I do this 3 times then heat to 1500 place in a bucket of Bakelite and let slow cool(takes about 6-8 hours.I then do my rough grinds tale to 220 grit. Hand sand with 220 from riccosso to tip till all vertical grind lines are gone. I leave the edge about as thick as a dime. sand edge(dime width ) from riccosso to tip.
With 1095 you need a fast quench. I use Parks 50. I also use water.with a layer of parks 50 about a half inch deep floating on top. I recommend the Parks 50.
I heat the blade to 1500/1525 and let soak about 5min then straight to quench Oil at 120F, water at 80 F . If using oil (P-50) I move the blade in a cutting motion in the oil till cool. using water I do a 2 seconds in, 2second out, 2 in, 2 out, back in to cool.
I then remove all clay or scale with a wire brush. I do not preheat my oven. I place the blade in the oven and bring the oven and the blade up to temp, about 425f once up to temp I hold at 1 hr. I run this cycle twice.
I don't have all the tech-no knowledge as to why this works. It just works well for me.
I hope this helps.

[WBE]

Ranger, just a suggestion. Try this on a piece of scrap 1095, and compare the grain size to another piece of scrap using your method. Bring up to 1525, soak for 5 minutes, air cool. Then bring it to 1300 and air cool 3, or 4 times. No soaking, but let cool in between until you can handle it. Bring up to 1500, soak 5, to 10, quench in the Parks, but heat it to 130, break it and compare, with magnification if possible. I think you will see a tad bit smaller grain. A slow anneal usually causes the grain to coarsen. Even if you stick with your method, if you were to do the 3, or 4 1300? cycles, after your slow anneal, and just before you do the final heat and quench, you should see smaller grain, and have a tad more strength in your blade. Try it one day when you're bored, or looking for something to do.

[ranger1]

Thanks WBF, I will do that. I am always looking to make my blades better.

[dbalfa]

I've learned something from this thread....I've got a couple of 1/8 x 18" sticks of 1095 I'll sell cheap if anybody want's them!

[DaveRuhlig]

Thanks for all of the input guys! I suspected overheating may be the issue especially as it seems to happen only on larger blades. By the time the whole blade is non magnetic the tip is probably too hot. I'll try some of the suggestions above. I know the perfect solution is a controlled HT oven but I'm struggling to justify the expense of my hobby already! As suggested, I'll also give 1080 a shot. So for I've only used 1095 and 01 in hopes of perfecting 1 of the 2 - maybe it's time to push thenm aside and try #3 or pony up for the oven. Thanks Again!!
-Dave

[Frankallen]

Hey Dave....Let me just put in my 2 cents. I have probably made about 10 knives with 1095 and been very lucky, have not had one to crack. Here's what I do, I HT in a barrel grill with real charcoal. I place the blade at an angle so the tip hopefully don't get too hot. As soon as it gets at critical, I give it about 15 more seconds and quench FAST!!!!! I use Automatic Transmission Fluid for quenching...I check with a magnet at critical without removing the blade from the fire. Everything Right, I love 1095!!!Hope this helps Bud!!

Frank

[WBE]

I think you will quickly fall in love with 1080/84. Do not look at it as an inferior steel because the carbon is a tad lower. Much of 1095 is acually closer to 1090, and sometimes less. Well HT'd 1095 only beats 1080/84 by hair or two in performance, and is just so much more forgiving in the HT. 1080/84 is also deeper hardening than 1095 due to having more manganese. As far as 01, it's my favorite steel, but is impossible to HT correctly without a controled heat source such as an oven, salts, or a propane forge arrangement with a heat control, and decarb protection is advised. 01 requires 20 minute soaks to come into a full solution with good carbon distribution. Ovens are great, but you also should aim for 5 gallons of commercial oil to go with it. You will likely choke at the price of it, but it will outperform, and outlast most, if not all, of the grocery store oils.