Which steel?

O

Oldquacker

Member
I was going to order some 1095 blade steel and they give me the option of CRA or HR. I have never ground any steel before so my question is what do I want? I would like to try and do the heat treating myself. There is so much that I don't know that I don't even know what I don't know.
 
Oldquacker said:
There is so much that I don't know that I don't even know what I don't know.
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.... and that absolutely proves that you know so much more than those who think they know. :biggrin: May I suggest that you consider something other than 1095 for your project? Something in the range of 1080 - 1084 would be much more forgiving in heat treat - especially if you are going to do it yourself. Any performance difference in the blade would be negligable IMHO.

(...and no, I don't know. Just an opinion.)

Rob!
 
Go with CRA on any 10x steels if you can.
The hot rolled, in my experience, has hard spots in it that booger up your drill bits and skin (mill scale) that's quite hard most times. Soak the HR in white vinegar for an hour or so, let it think about what it's done.

Rudy
 
Knifemaker.ca said:
.... May I suggest that you consider something other than 1095 for your project? Something in the range of 1080 - 1084 would be much more forgiving in heat treat - especially if you are going to do it yourself.

Rob!
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Thats the kind of advice I am looking for. What do you mean by much more forgiving? Why will it be:les:
 
The 10xx are 1095, 1084 and such, I guess it could be anything from 1000 to 1099 but I wouldn't know. It is my understanding that O-1 is slightly more corrosion resistant than 10xx and it is also supposed to be easy enough to heat treat yourself. It comes precision ground usually which is a bonus but is more 'spensive than 10xx. I am by no means learned in such matters but I am told that O-1 i a very good steel. Not all O-1 is the same though, make sure it is AISI O-1, that way you know it is good. I have worked with only 1095 and O-1 and I would take the O-1. Go with CRA as well if you are going to heat treat it yourself. I have little experience myself but I am good at regurgitating what others have said.
 
Are you going to do stock removal or forge? If I were doing stock removal I'd get an air quench steel and surface ground like A2. It's not too expensive and doesn't warp.
 
10x.......simple non alloyed steels such as 1065, 1075, 1080-5, 1095. Notice the "10" in front of each one. I use a lot of O-1, but if you work it hard or forge, it can stand for an annealing. O-1 partially air hardens with heat. The carbides will eat your drill bits for snacks. Being an alloyed steel, it's time/temperature sensitive so you're better off with a real heat treat oven. Don't let that scare you away from it though, when I had to, I did HT in my forge. You probably won't get optimal results without the oven. Rob had the best advice unless you do some homework and have adequate tools.

Rudy
 
Sticks said:
Are you going to do stock removal or forge? If I were doing stock removal I'd get an air quench steel and surface ground like A2. It's not too expensive and doesn't warp.
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Yes I will be doing stock removal. Thank you all very much. I will be ordering some steel and maybe I should order several types like some 1080, O-1 and some A2.

Man, I wish I had a seasoned knife maker next door.

Kent
 
Oldquacker said:
Thats the kind of advice I am looking for. What do you mean by much more forgiving? Why will it be:les:
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1095 has some some extra carbon that can cause havoc. (I don't pretend to fully understand how). The result is that, when quenching the steel, there is a very fine line line between breaking the blade (quench too fast) and not hardening (quench too slow). 1084 has just the right amount of carbon for hardening - without the havoc.

There is so much that can go wrong in heat treat that you need to have a good reason to invite the s**t disturbers.
 
Kent,
My suggestion to get A2 may be bad advice if you intend to do heat treat without a heat treating oven. Others here will know better than I about whether you could treat it using a magnet, etc. But, if you're new to this I'd suggest getting flat ground O1, removing the scale with a platten is no fun IMHO! And although you didn't ask, I get cold rolled steel when ordering stainless for bolsters guards, etc. It is just more "finished" in terms of flat and square than hot rolled.
Jay
 
Ok, let me see if I can do this without confusing people too much. The reason that steel with a high carbon content causes problems is due to something called retained austinite. Austinite forms when you heat steel above around 1430°. This is a good thing at at this point. It allows carbon to dissolve into the iron in the steel which in turn is necessary to harden steel upon quenching. However, with steels that are above around 0.77% carbon this can cause the austinite not to convert to the hardened crystal of steel, known as martensite, and the austinite is retained, thus the name retained austinite. This will happen if the steel is heated too hot for too long. Now this really is not much of a problem until the carbon level gets above 0.85% carbon. A little retained austinite is not much of a problem but above 0.85% carbon a significant amount of retained austinite is formed. The problem with it is that retained austinite is not stable. It wants to form martensite and will over a period of time as stresses are applied to the steel. This martensite will be untempered and very hard and will increase the brittleness of the steel in higher concentrations.

1095 steel is around 0.95% carbon, note the last two numbers in the designation code, so it falls into the group of steels that can have a problem with retained austinite if heated too high for too long putting too much carbon into solution. After you get some experience under your belt and learn how to control the heat that you apply to your steel as you heat treat it's a good knife steel that a lot of makers, custom and commercial, use. To begin with, many recommed to beginners that they avoid such steels to start with.

If you are lost with the terminology or are unfamiliar with heat treating I suggest that you go the the metallurgy and heat treating section of this board and read the subjects within the sticky at the top of the page, Heat Treating Tool Box. Better yet, print it out. It will be enough to get you started and allow you to understand better the discussions on these boards.

Doug
 
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If you are doing stock removal you want CRA. CRA means "cold rolled & annealed) HR means "hot rolled". The CRA will be softer and easier to drill and grind. But if you are going to heat treat it yourself I suggest you do yourself a favor and get some 1084 from Aldo at www.njsteelbaron.com.
 
Doug, what you said makes perfect sense. I am following what you are saying on the amount of carbon content. The best thing I did was ask a couple questions on this sight. It has saved me potential greif and money. Thanks again to all of you. :happy:

Kent
 
May I suggest you begin with one steel type and use it until you understand it and its properties before you add another steel to your stock room. I say this becaise as a beginner you want to be producing the best results you can to improve your skills as best you can. This involves understanding and being able to control the media you are working with to the best of your ability. Once you have the knowledge and the know how on one particular steel, add another. This will help you to make decisions about your work more quickly and accurately. The alternative is to constantly refer to charts graphs and other peoples input during your making process. I personally recommend starting with 01.
I hiope this made sense.
 
Doug Lester said:
Ok, let me see if I can do this without confusing people too much. The reason that steel with a high carbon content causes problems is due to something called retained austinite. Austinite forms when you heat steel above around 1430°. This is a good thing at at this point. It allows carbon to dissolve into the iron in the steel which in turn is necessary to harden steel upon quenching. However, with steels that are above around 0.77% carbon this can cause the austinite not to convert to the hardened crystal of steel, known as martensite, and the austinite is retained, thus the name retained austinite. This will happen if the steel is heated too hot for too long. Now this really is not much of a problem until the carbon level gets above 0.85% carbon. A little retained austinite is not much of a problem but above 0.85% carbon a significant amount of retained austinite is formed. The problem with it is that retained austinite is not stable. It wants to form martensite and will over a period of time as stresses are applied to the steel. This martensite will be untempered and very hard and will increase the brittleness of the steel in higher concentrations.

1095 steel is around 0.95% carbon, note the last two numbers in the designation code, so it falls into the group of steels that can have a problem with retained austinite if heated too high for too long putting too much carbon into solution. After you get some experience under your belt and learn how to control the heat that you apply to your steel as you heat treat it's a good knife steel that a lot of makers, custom and commercial, use. To begin with, many recommed to beginners that they avoid such steels to start with.

If you are lost with the terminology or are unfamiliar with heat treating I suggest that you go the the metallurgy and heat treating section of this board and read the subjects within the sticky at the top of the page, Heat Treating Tool Box. Better yet, print it out. It will be enough to get you started and allow you to understand better the discussions on these boards.

Doug
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Not to put too fine a point on it, because this does answer the question of why you are better off buying a eutectic steel like 1080,1084, Some of the information is incorrect.

I will respectfully make these points, This is how I understand it, so someone can correct me if I am wrong.

1, you said. "
it falls into the group of steels that can have a problem with retained austinite if heated too high for too long putting too much carbon into solution"
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When you are heating a blade for quenching you WANT all the carbon to go into solution. The reason we don't want to heat for too high for too long is because it causes grain growth. large grain=weak steel.

While temperature is extra critical in hyper-eutectic steels,it is critical with any steel, so that is not the main problem.

The main problem with all that "extra" carbon lies in the cooling process that we call quenching. At critical temperature the micro structure is austenite. When austenite is cooled extremely slow, it will form large ferrite crystals filled with spherical inclusions of cementite. This microstructure is referred to as "sphereoidite." If cooled a little faster, then coarse pearlite will form. Even faster, and fine pearlite will form. If cooled even faster, bainite will form.

The problem with that, is that NONE of those microstructures are desirable in a Knife blade, at least not on the cutting edge. The trouble with 1095 is that it's "window" for perfect cooling speed where most of the steel forms martensite is very narrow. That makes it an unforgiving steel. It just doesn't really know what to do with all the extra carbon, so unless you have the experience, tools and equipment to get everything right, your results will be poor, or unpredictable.

Ricky
 
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Lagrange said:
May I suggest you begin with one steel type and use it until you understand it and its properties before you add another steel to your stock room.
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That's what I just did. I just ordered several thickness's and width of CR1084. I was going to buy a peice of 0-1 too but they were out of stock.
 
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