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View Full Version : Im very sorry for this but another Hamon question lol



Lerch
10-26-2011, 09:28 PM
Well my 1095 steel from Aldo should be in hopefully tomorrow and if that happens then i plan on trying my first differentially hardened knife blade this weekend. Here is a quick supply list i will have on hand:

1/8" 1095 Aldo steel (hopefully)
Parks 50 Quench Oil
Satanite clay
EvenHeat Oven

I have read Stephan Fowlers tutorial and found it very helpful but having never worked with carbon steel or anything other than plate hardening stainless steels. Any way any one could give me a short little break down on how to do this thing? I understand to apply a very thin layer of clay over the entire blade first, then about 1/16" nicely smooth and even finished layer over the spine area and where ever else i want it. Now once this is dry i will heat treat, this is where i am a little lost since i will be using a Evenheat to HT, everything i have done i have wrapped in steel foil so if anyone could give me a little info from this point through oil quenching i would love it!!!!


thanks
steve

Lerch
10-27-2011, 08:33 PM
well my steel came in today, so i really hope someone will let me know something cause i cant wait to try it ths weekend!!

thanks
steve

Doug Lester
10-27-2011, 10:09 PM
I've done clay quenching for differential hardening, not a hamon, and I've not use 1095 for years, never Aldo's at all, but I will give it a try. Have everything ready to go for when you pull the blade out of the oven. That means pre-heat the oil and have the tempering oven at the temperature you want it. Have the quench tank close enough to the oven so that you need take no more than one step towards it to get the steel in the quenchant. I would soak the blade in the oven for 5 minutes at 1425 degrees to get the carbon well disolved into the austinite. That is about 100 degrees above the A1 point according to the ITT diagram that I have. If you wanted to go to 1450 degrees it probably wouldn't hurt. When you take the blade from the oven you must move directly and quickly to get the blade into the quenchant so that is above wht A1 point when it enters the quenchant whether you put it in edge or point first. One other thing in the preparation of the steel, before I forget it, normalize the steel three times to reduce the stress in the blade and to make sure that you have fine grain before you coat the blade with clay. I know that you are doing stock removal but it won't hurt. It might not be as necessary as with forging but I have no idea what stresses there may be in the steel that Aldo sells or what the grain size is.

At this point some people do an interupted quench. They will leave it in the quenchant for three seconds, that's plenty of time to miss the nose of the curve, and then take it out for three seconds, back in for three seconds again, then back out for three, then return it to the quenchant until the steel drops to about the temperature of the quench. I have never done this, even with the 1084 that I just used to make two choppers that are on my bench, nor do I agitate the blade while it's in the quenchant.

When the steel is cooled to about the temperature of the quenchant I take it inside and scrub the oil off the blade with detergent under hot running water and then put it immediately into the hot oven, 400 degrees should be a good starting point, though 375 degrees might not be bad. If the steel comes out a little too hard all you will need to do is up the tempering temperature by 25 degrees and try again. If you get it too soft you will have to do the whole clay coating and quenching thing again before you can retry the tempering at a lower temperature. Do at least two tempering cycles, I recommend for two hours each. A third cycle won't hurt anything even though this is a simple steel.

I hope this helps.
Doug

Lerch
10-27-2011, 11:02 PM
Thank you Mr Lester for your response, thanks for the info and if you dont mind i have just a couple of questions

Though i cant imagine so, i have to ask since i have always foil wrapped my blades, but i dont foil wrap these blades after i dry the clay on them when i HT do i ?

I had read that i did not need to pre heat Parks 50 oil unless it was very cold outside, its been about 50-60deg here, if i do need to preheat then what temp? is it 130deg like i had read with other quenchents?

If i need to preheat the oil would it be okay to use a crock pot cooker on whatever setting would give me the closest temp to whatever is needed?

How do i "normalize" the steel? I am assuming this involves soaking it a some temp for a given amount of time as a stress reliever, could you please tell me how to accomplish this? and is this something i would need to be doing with my stainless stock removal steels i have been working with???

So just to clarify I just lay the blade in the quenchent or do i suspend it while holding on to the tang or should i try the interupted quench like you were talking about ?

Thankyou very much again for your response, i cant wait to try this!!


thanks
steve

Doug Lester
10-28-2011, 01:26 AM
I wouldn't foil wrap the blade because it will slow the cooling if you put it into the quenchant with the foil on and if you try to take it off first the steel will cool too much and form pearlite.

On the Parks #50, my understanding is that you might want to take it up to about 90 degrees. You have to remember that I've never used it and I'm going by what I remember from other posts. A crock pot cooker should do alright if it is deep enough. Just keep an eye on it with a thermometer, a candy thermometer will do, to make sure you don't overheat it. Another poster on one of the boards I go to found out the hard way that Parks #50 has a very low flash point. Perform the quenching outside and have a cover ready to go onto the pot if you have a fire.

To normalize the blade all you are going is allowing the crystals to reform so all you have to do is austinize the steel and allow it to cool to a black heat in still air. You don't have to soak the steel because you're not worried about disolving any carbon at this point.

In something like a pot I would put the blade in point firest whle holding the end of the tang with plyers or tongs. Don't quench the tang becuase you don't want to harden it. If you do you will have problems drilling it later. As far as interupted quenching, it's probably more critical when using water or brine. I've never done it, even when I used brine, but that's only with two blades. You can try it if you want, that's really up to you. If I was doing it I would just hold the blade in the quenchant with the tang out until the tang was at a dark heat and then cool the whole thing in the quenchant if the container is deep enough. After it's all down to where it's comfortable to handle I would scrub the oil off in hot soapy water and then get it right into the tempering oven.

Doug

Doug

Lerch
10-28-2011, 09:09 AM
Thank you again sir for the info

so on the normalizing do i just bring it to the 1425deg mark in my oven and then take it out and air cool with no temp soak time?

The crock pot i am wanting to use has a good lid so that should help me in the case of a fire, hope to avoid it though lol

I guess my only last question would be that about the normalizing, what is the process just so i can make sure i do it right, i will be using a Evenheat oven

thanks much
steve

Doug Lester
10-28-2011, 12:09 PM
Yes, that all there is to it. Bring it up to austinizing temperature for just long enough to make sure it heated throughout and then letting it cool. What's going on is that when steel changes phases, body centered to face centered crystals or visa versa, new crystals form at the boundries of the old crystals and are smaller than the original crystal. By going through multiple cycles the iron crystals in the steel become smaller and smaller. The thing to watch is not overheating the steel and soaking it or you can actually grow the grain. That's why you try to keep the temperature to just high enough to austinize the steel.

Doug

Lerch
10-28-2011, 12:59 PM
Thank you,

so i would do this about 3 times right? is this something i would need to be doing with the CPM154cm that i have been using or other stainless steels?? if not necessary would there be any benefit to doing it anyway?

would there be any benefit to LN cryo treating the 1095 or other carbon steels after HT???

thanks
steve

Doug Lester
10-28-2011, 01:28 PM
You can't normalize any air quenching steels such as stainless steels. You could anneal them to relieve stress and multiple quench if you are worried about grain growth. Not all stock removal people normalize steels that can be but it's easy with carbon steels and you can build up uneven stresses in the steel while grinding. You don't need to correct for grain size if you are sure that the stock you are using has acceptable grain. The alloying elements in stainless steel also tend to counter grain growth, If in doubt, I think that it is best to make sure that you don't have large grain in the steel.

Cryo is a waste of time and money when dealing with carbon steels especially those that quench in oil or water. The actual Mf point, most ITT diagrams only give M90%, is above room temperature and all you are doing when you stick it in a cryo bath is to make it cold. I know that there is a master knifesmith who likes to stick his carbon steel blades in the freezer; it doesn't hurt but it's doubtful that it helps anything. It takes a pretty complex steel to have an actual Mf point that is below zero degrees.

Three cycles is the standard for bladesmiths but you may well get by with just a couple for stress relief. It is doubtful that you are dealing with the grain sizes that we deal with. Just don't expose the steel to really high temperature, like above 1500-1600 degrees, for long periods of time. Temperature is the main factor in grain growth and the higher the temperatur the quicker grain growth will occure.

Sorry if some of the things that I say are a little confusing. I have to try to get out of smith mode and into stock removal mode.

Doug

Lerch
10-28-2011, 02:12 PM
your not confusing at all, im just learning as i go and this is my first time with carbon steel, thanks for all the help and i think that answers most any question i can come up with. well one more little question :)

when i get the steel to 1425deg i just take it out of the oven and let it cool in open calm air? should i hang it or just hold it with my tongs? i guess i will just allow my oven to hit the 1425deg mark and then take them out, should i let them cool to hand temp and them restart the process?

thanks
steve

Rudy Joly
10-28-2011, 03:25 PM
When normalising, it goes quickly.
On 1095 I do the first cycle at 1450....take it out of the oven with tongs and hold it untill there's no more color in the blade, black heat. Then right back in the oven at 1425 two more times letting the blade cool to black heat each time. Each time I remove the blade, my oven loses about 300 degrees from opening the door and In my case is back up to temp by the time the blade has lost it's color. It's a fairly quick process. After a couple blades you'll wonder why you worried so much like I did.

Rudy

Lerch
10-28-2011, 04:37 PM
Thankyou for the info, thanks for the layout of what to do, i appreciate it!

thanks
steve

McClellan Made Blades
11-01-2011, 03:54 PM
Rudy,
I don't mean to dispute you but 1425 seems a little low for 1095, I know you can read the ITT charts...and I can't. I actually can't remember where I got my HT info for 1095, I haven't used it in a while, and since it's programmed in my kiln, I rarely ever have to look up HT info for the steels I've HT's before. The number 1550 keeps coming to mind, I don't know why, the only time I would hop up and dowm saying, "I'm right", is if I had just gotten done HTing one and it's been a long time since I used it. So I'll just ask nicely, k?

If you check out my avatar, that IS Aldo's 1095, it produces the wildest hamons I've been able to do on any steel much less 1095, that was until I got my W-2, which is known for it's ability to create a wild hamon. If you haven't used Aldo's BIG 1095 it is a treat and a PITA at the same time, this stuff is 3/8" THICK!!! But if you're into hamons, AND forging, it is awesome! Rudy, did you see the water bottle cut I did last year? This is the knife I used in the video, scarey sharp!!!

Lerch, in your list of supplies, I didn't see what your using to sand and polish the blade with. The way I was taught, I'm guessing my way is different that what every one else is doing, if you'd like my instructions, due to the size of email it will be HUGE, it's much easier if I send it to your home email, because it is very long, send me you personal address, and I'll send you the details, of how I do it. I also didn't see some sort of acid in that list ( I coul dhave missed it, I usually miss the obvious!! Radio Shacks PCB Etchant is what most of us use. Acid is the best way to get the hamon to POP! Without it, you've done a lot of work with little to show for it! Not saying it WON'T show, if it's done correctly, you will be able to see a shadow of a hamon during handsanding, I'll help the best I can, if you'd like. Thanks, Rex

Rudy Joly
11-01-2011, 04:44 PM
Hi Rex,
This is just the handiest reference I had at the moment, but not the one I use. The basic info is all here though. I've been using my numbers with good results for years. 1425 is only the low end of my normalizing temps. Bear in mind I'm not the last word on heat treating and only pass on info that I'm confident in through practical use. According to these numbers, your 1550 is close to normalizing or annealing temps. But I'll stand my ground on hardening at 1450 for a hamon......it works. I can't argue with success.


SAE 1095 Carbon Tool Steel:


--------------------------------------------------------------------------------
Normalizing: Heat to 1575F (855C) cool in air. (note no holding time).

Annealing: "As is generaly true for all high carbon steels, the bar stock is supplied by mills in spheroidized condition. . . . . When parts are machined from bars in this condition no normalizing or annealing is required."

Forgings should be normalized.

Anneal by heating to 1475F (800C). Soak thoroughly. Furnace cool to 1200F (650C) at a rate not exceeding 50F (28C) per hour. From 1200F (650C) to ambient temperature, cooling rate is not critical.

Hardening: Heat to 1475F (800C), Quench in water or brine. OIL QUENCH sections under 3/16" (1.59mm).

Tempering: As quenched hardness as high as 66 HRC. Can be adjusted downward by tempering.


--------------------------------------------------------------------------------
Heat Treaters Guide - Standard Practices and Procedures for Steel. 1982, American Society for Metals, p.81

Rudy

Doug Lester
11-01-2011, 04:55 PM
The problem with ITT diagrams for hypereutectic steel like 1095 is that the Acm points are not listed, just the A1 point. The iron-carbon phase diagram that I have that was published by Verhoeven would put the Acm point for 1095 by carbon content at 1500 degrees. If you were wanting to get you steel just hot enough to disolve the carbon from the cementite 1525 degrees would do it and probably not cause enough grain growth with a short soak to be concerned with. I you wanted to keep your austinizing temperature between the A1 and the Acm points to reduce grain growth then something like 1425-1450 degrees with a longer soak time would be better.

Doug

Ok, from the post that Rudy was putting up at the same time that I was typing, the 1475 degree austinizing temperature would still be between the A1 and the Acm points.

Rudy Joly
11-01-2011, 05:07 PM
Thanks Doug....I think(?).
Like I said, I'm not a heat treat guru but my recipe that I use was sniped from a couple of makers back in the 80's. Once I started using it / their recipe, the results spoke for themselves. I even still use brine like they showed me with very few heartbreaks.

Thanks,
Rudy

Doug Lester
11-01-2011, 10:25 PM
The point is both methods would probably work and it would probably take some microscopic examination of the crystaline structure to say which is better. The text books state that hypereutectic steel is more prone to grain growth if heated above the Acm point than hypoeutectic steel is if heated above the A3 point. However, other things factor in, like whether aluminum or silicon was used to deoxidize the steel. Another factor is that when these texts and tables give heat treating data they are usually talking about steel in greater cross section than knife blades. That also changes the mix of variables. Then there is the factor that there is 1095 and there is 1095. I got some 1095 from Admiral that I was only able to harden in brine. Aldo, aka The New Jersey Steel Baron, brought some 1095 to a hammer-in last that I attended that hardened just fine in oil and produced a hamon.

Doug

McClellan Made Blades
11-02-2011, 10:41 AM
Hi Rex,
This is just the handiest reference I had at the moment, but not the one I use. The basic info is all here though. I've been using my numbers with good results for years. 1425 is only the low end of my normalizing temps. Bear in mind I'm not the last word on heat treating and only pass on info that I'm confident in through practical use. According to these numbers, your 1550 is close to normalizing or annealing temps. But I'll stand my ground on hardening at 1450 for a hamon......it works. I can't argue with success.


SAE 1095 Carbon Tool Steel:


--------------------------------------------------------------------------------
Normalizing: Heat to 1575F (855C) cool in air. (note no holding time).

Annealing: "As is generaly true for all high carbon steels, the bar stock is supplied by mills in spheroidized condition. . . . . When parts are machined from bars in this condition no normalizing or annealing is required."

Forgings should be normalized.

Anneal by heating to 1475F (800C). Soak thoroughly. Furnace cool to 1200F (650C) at a rate not exceeding 50F (28C) per hour. From 1200F (650C) to ambient temperature, cooling rate is not critical.

Hardening: Heat to 1475F (800C), Quench in water or brine. OIL QUENCH sections under 3/16" (1.59mm).

Tempering: As quenched hardness as high as 66 HRC. Can be adjusted downward by tempering.


--------------------------------------------------------------------------------
Heat Treaters Guide - Standard Practices and Procedures for Steel. 1982, American Society for Metals, p.81

Rudy


Rudy,
I'm sorry, the way I read it was that 1425 was the HT temp, I must have misunderstood that, and with my recent success HT'ing W-2, it is on my mind all the time, the temps, soak time, etc. That is about the only way I can retain it, my memory is damaged or should I say my brain is! It's along story, lets just say I had Dain Brammage about 10 years ago and my memory is'nt very good, it's mostly short term, but at times it's long term too! The stuff I do remember is ALWAYS the freakiest stuff. With no rhyme or reason to any of it. I see now your talking about normalizing temps, so keep it going, it's very interesting, Rex