Thread: steel choice and heat treat for beginner in canada

so far i havent been able to find any suitable razor steels locally.. perhaps some 440 which i understand is a stainless steel that may not be the easiest to work with or the best material.

im currently working with a coal forge with a hand crank blower, and dont have a pyrometer, though i might buy an infrared pyrometer if it is worth it. i've practiced a bit with mild steel, forging a bit, and grinding a bit on a bench grinder.

reading what i can on this forum about steels for beginners it seems like the following are recommended:

10xx steels from perhaps 1075 to 1095. it sounds like 1095 might be the "best" out of those, though 1084 or 1080 might be easier to HT. is there also 1085 as a steel grade?
i dont know about 1095, but i think folks have said that you have 1-2 seconds to go from heat to quench with 1084, instead of 1 second for O1. is this correct?
the 10xx steels want a fast quench.. many say water works better than oil, though a greater chance of cracking the blade. as i understand it brine quenches faster than water, is there also an increased risk of breaking the blade? some oil quench 10xx, in this case (or perhaps in all oil quenches period?) the oil is heated oil to reduce viscosity and speed up the quench (pot of oil on a hotplate with a thermometer?).. 10xx steel seems to be the cheapest steel of the steels i am considering.

O1 is said to be another easy steel to HT, though things can be more complicated that 10xx, how i dont know.
O1 requires a longer soak time than 10xx.. if i soak and get the temp higher than i need it is this a problem? O1 is an oil quench.. if i work with a commercial quenchant, and cover in foil (aluminum foil?) to temper will i stink up an oven doing this?

W1&W2 dont know much about these steels other than they are water quench, Charlie (spazola) i think uses w2 sometimes.. and one or both are said to be shallow hardening which isnt (i think) necessarily an issue with a razor as it isnt very thick.. any comments on w1 or w2? w1 and w2 are also not as cheap as the 1084 i can find..



so.. it seems like heating O1 /may/ be more difficult, and quench needs to be done quicker, but quenching it may be less likely to break the blade. still not sure on choice of quenchant considering i may be using an oven to temper..

seems like 10xx is cheaper and simpler to heat, though rate of breaking blades may be higher (at least if i use water or brine)

the difficulty of tempering either seems about the same..

at the moment im considering 1084 in 1/4"x1" from Aldo Bruno (the NJ Steel Baron) in New Jersey.. anyone have any Canadian options?

anyone have any comments on using a hand crank coal forge for HT, or an oven for tempering? what kind of magnet do you folks use, how do you manage a hot piece of steel and a magnet (attach the magnet to something?) does the currie<sp?> point change much for different steel? can i practice bringing a piece of mild steel up to temp just to get used to the process and colours and such and apply that to high carbon steel?

im guessing getting a good thermometer to check your oven's temperature may be a good idea..


lotsa questions.. i've read a bunch, enough to have lotsa questions, but not enough to know all the answers, or enough experience to know what i do and dont need to know to get started..

Try a local machine shop, they will have a supplier with reasonable shipping.
Eric

You've done a good bit of homework. I see good evidence of thoughtful questions as a result. I'll try to give you helpful answers in turn.

Originally Posted by ezpz

440 which i understand is a stainless steel that may not be the easiest to work with or the best material.

A lot of fair to middling knives have been made of 440C (there are also 440A and 440B steels). You can sharpen it and it will work well if you hit the sweet spot. Generally getting the heat treatment done well is the trick. Stainless steels require good thermal control to heat treat well. In this case, it might be better to have a blade of stainless stuff professionally heat treated.

im currently working with a coal forge with a hand crank blower, and dont have a pyrometer, though i might buy an infrared pyrometer if it is worth it. i've practiced a bit with mild steel, forging a bit, and grinding a bit on a bench grinder.

Your tool set makes me recommend that you tend toward the less complicated steels in the 10xx series. They will be a lot more forgiving in that kind of forge atmosphere. A lot of good blades, through history, have been forged and heat treated in similar fires long before the modern era. But you will have a whole different set of things to watch out for, to compensate for. Not least is that you will have ground a razor to quite thin and then are putting that into a very aggressive forge atmosphere where steel can burn easily if not thought about. You will need to grind less up front and grind more after heat treating to adjust for that. And, watch and learn the fire over lots of blades to gain the necessary eye and experience to tell you when it's good enough or too much. You will ruin any number of blades doing this.

It's not harder, just different. I do not recommend racing off after the best tools when you haven't finished learning the basic tools yet.

The infrared pyrometers I've found that are cheap generally do not have the temperature range for forging and top out at about 1000F. Getting an IP for the full range of forging to heat treatment will be far more expensive. If you could find an old optical pyrometer (scarce in working order) it would be worth it. I've been looking for one of those myself for years.

...10xx steels

Yes, stick to the simple carbon steels. The oil quenching steels are acceptably close to the 10xx steels that there is no critical difference for the way you have your shop setup. Most 10xx steels will harden in oil and gain a few points or so of hardness in water. Oil quenching steels do not do well in a water quench. Water quenching steels require water and do not perform well in oil quenches. O-1 and W-1 are readily available from machine tool suppliers like Enco or MSC and cheap.

the 10xx steels want a fast quench.. many say water works better than oil, though a greater chance of cracking the blade. as i understand it brine quenches faster than water, is there also an increased risk of breaking the blade? some oil quench 10xx, in this case (or perhaps in all oil quenches period?) the oil is heated oil to reduce viscosity and speed up the quench (pot of oil on a hotplate with a thermometer?).. 10xx steel seems to be the cheapest steel of the steels i am considering.

Yes. Do not use brine, it's simply not needed. Yet, the myth continues to linger on. Water will crack blades too. Success in this area is learning to get the heat right and knowing how long to stay in the quench. Frankly, a lot of that is feeling the blade. Small razors with thin cross sections are not going to give you very much time to feel it before it's gone. Oil is safest and will produce acceptable hardnesses for your first blades. Good old canola oil is cheap. Warm oil has some benefits but is not an absolute requirement.

O1 requires a longer soak time than 10xx.. if i soak and get the temp higher than i need it is this a problem? O1 is an oil quench.. if i work with a commercial quenchant, and cover in foil (aluminum foil?) to temper will i stink up an oven doing this?

Yes, about five minutes or so. In a coal fire, this is more time for the temperature to overshoot critical. It's more time available to burn off part of the blade unless you are very careful or setup the fire to avoid this. You won't need foil to temper O1. Canola oil smells like fries or chips. You might be able to conceal your efforts from the Oven's Owner and live to see another day. Much better than used motor oil or transmission fluid in the cooking oven. LOL.

W1&W2

Both good steels. And more expensive to some degree but not as expensive as some others. 1084 and some like it will have more manganese as an alloying element. These kinds of steels will through-harden instead of being shallow or low-hardenability steels. You will need to know the difference because this has an impact on how you will quench them. During the early attempts, a cheaper steel is less painful when your efforts produce scrap.

anyone have any comments on using a hand crank coal forge for HT, or an oven for tempering? what kind of magnet do you folks use, how do you manage a hot piece of steel and a magnet (attach the magnet to something?) does the currie<sp?> point change much for different steel? can i practice bringing a piece of mild steel up to temp just to get used to the process and colours and such and apply that to high carbon steel?

One of the best ways (assuming your only source of heat is coal or charcoal) is to bury a closed end pipe into the hot part of the fire. Then hold the blade inside the pipe. The pipe warms up, the radiant heat will warm the blade and there is no direct impingement of the fire on the blade where you are most likely to burn away good steel. Plus, you will be able to see the blade and better judge the colors for proper heat. With a magnet and your eye, eventually you will train the wet computer to recognize the right conditions and you'll likely use the magnet less frequently.

If you really wanted to improve the atmosphere inside the pipe, toss a small piece of charcoal down the pipe and all the oxygen will burn out leaving a nice clean reducing atmosphere. This reduces scale formation a lot. All that's left is to play with time and temperature to get it all right. You'll eventually burn up pipes doing this but that is a small cost compared to the price of all that hard work on the blade steels. DO NOT USE GALVANIZED PIPE, use black iron pipe.

Attach the magnet to the forge frame where you can reach it easily. You want to be able to feel the magnet trying to stick to the hot steel but not get stuck because then the magnet will start cooling down your blade. For similar class steels like the 10xx, the curie point is not so different that the use of a magnet will give you too much error.

im guessing getting a good thermometer to check your oven's temperature may be a good idea..

This is an ideal working setup. Home ovens have some swing around the set point that is allowable for cooking things where a few degrees is not that big of a deal. Toaster ovens can swing 50 degrees and that could make a mess of a tempering operation. If you knew how much the set error was for an oven you could compensate nicely.

I think I got most of these halfway answered.

i cant remember if i talked to the local machine shop that i know about or not.. i think i did, and i think they werent interested in selling small amounts of barstock unfortunately.. i should check again.

so if i decide to send out for HT 440 is an option for a razor? if im not concerned about using SS in particular will i get better results from 10xx if both are sent out? SS might be nice for a product, though for myself i think i'm just as happy working with simple HC like 10xx or O1, although i might be able to get 440 locally.. by the sounds of it cpm154 or maybe 154cm would be better than 440, but i dont think i can get that locally.

i had heard of using the pipe with a piece of coal, and it sounds like the way to go.. didnt know not to use galvanized pipe.

so overshooting the critical temp on O1 is not a good thing, and working with my setup i should stick to 10xx, although O1 is still doable..

ok so i take it 10xx isnt specifically a water quench, and i can use room temp canola with less cracked blades than water, but it wont harden quite as much.. that sounds alright..

i've heard some folks mention that from one smelt to the next a given grade of steel can vary even from the same foundry.. for the sake of getting consistent results should i buy more than just a few bars, or are the differences going to be smaller then the differences in my own technique? i'm thinking of buying a bunch of 1084 as the shipping will be the same whether i buy a few bars or 70 lbs (i think), and that might be reason enough to buy a lot.

thanks for your help epd and Mike..

Originally Posted by ezpz

i've heard some folks mention that from one smelt to the next a given grade of steel can vary even from the same foundry.. for the sake of getting consistent results should i buy more than just a few bars, or are the differences going to be smaller then the differences in my own technique? i'm thinking of buying a bunch of 1084 as the shipping will be the same whether i buy a few bars or 70 lbs (i think), and that might be reason enough to buy a lot.
.

At the level we're working, it won't make the tiniest bit of difference.
Any batch of O1 or 1084 is as good as the next.

The variance introduced by our heat treatment and time in the fire / working above critical temperature is much bigger than the tiny variance introduced from one batch of steel to the next. I've heard about Japanese knife smiths who buy large lots of a certain steel if they think it is more pure than others. Even if that distinction is real and meaningful, we're talking about people who've been hammering steel their entire life, and who can spot a 5 degree window around the critical temperature by the color of the steel.

We are nowhere near that

I use FlatGround.Com - Precision Flat Ground Tool Steel Stock and Drill Rod in O1, A2, D2, S7, and Low Carbon. for my steel, there are quite a few suppliers listed on the sticky as well.

You've already got some really good information. For some in depth stuff about heat treating knives (including particular steels), search for Kevin Cashen (ABS Master Smith). He's what one might call a bit OCD when it comes to the what's and why's of heat treatment.

Reference some of your questions, I'd also suggest 10xx steels, particularly 1084. It's a great carbon steel and many knife makers use it. 1084 will harden very well in oil, but not all oils are equal. There are engineered oils made specifically for quenching. 10xx steels are a fast quenching steel and since it seems you are seeking a deeper understanding, I'll try to provide some more information. When quenching, we need the steel to have reached Austenizing temperature. Once it's at the right temperature and the carbon in the steel is evenly distributed, we want to trap it there, so we quickly cool it, forming Martensite. (As you mentioned, this can be discerned with a magnet. I have one of those old all metal (not the black stuff) magnets they give to cows to swallow on top of my forge. That way I can take out the steel with my tongs and touch it to the magnet and see if it sticks.)

5160 for example is a slower quenching steel, meaning you can get good hardness out of it even though the cooling process took a bit longer. The reason for this is it has more alloys in it-still a good knife steel, just different. The alloys slow the process of the steel reverting back from Austenite, which means you have a longer window of time with the quenchant to harden it. This is where things differ with 10xx steels. There are fewer alloys in it, meaning there is a shorter window of time to turn it into Martensite.

That's not to say you can't have a very good knife without spending all kinds of money on electric kilns or engineered quenchants. I know an ABS Master Smith who used vet grade mineral oil for years as well as for his test knives. You just need to know your own process. For mineral oil or canola oil, I'd heat it up a bit to make it a quicker quenchant for 1084. I've seen several guys use hot water heater "coils" (?) to do this. They're those U-shaped elements. They just drill a hole in whatever steel container they have their oil in and put in the element and wire it to a switch. Stick in a thermometer and away you go-also helps when working in a freezing garage in the winter to bring it up to a manageable temp. On the other hand, if you buy an engineered very fast quenchant, be careful about heating it up like the others-it is possible to make it too fast and cracks/breaking can occur.

Hopefully that makes some amount of sense. Good luck and post pics-I really like looking at the customs guys make .


Jeremy

does anyone use 5160 for razors? i understand its a good knife steel, but only has .60 carbon.. is it suitable?

5160 would probably make a fine razor. You'd only have to suffer from others who thought that it didn't have enough carbon or had another value about how hard a razor should be. I remember Rockwell testing some blades that shaved pretty well according to their owner and they were Rc50.

It will easily achieve enough hardness, Rc 57, to make a good edge if the geometry is correct, and not be impossible to hone. Over the life of the razor it will wear more quickly than a harder blade. It will be tougher. The only way to know for sure is to make one.