HT Tests

[Eli Jensen]

Hey everyone, so I've been doing some experimentation on HTing 1095 and 1084 to get some practice and see what works best for me. Hoping some of you metallurgy gurus could give me some insight to whats going on. Here's what I've been up to today:

Using a discarded 1/16" 1095 blade for a neck knife, heat to dull cherry red, quench in pure heated canola oil. Progressively get the blade to a brighter color before quenching until it passes the file test and hammer test (bang with a hammer. doesn't shatter, fail). I got mixed results with canola oil. Also the sides of the steel flake while being quenched, whats up with that?

Then I used room temp water. Brought the steel up to orange/semi-bright orange according to my eyes under very dim lighting. At this color I get the file to skid and the steel to shatter with one strike. Much more consistent results with water than oil. Nothing below orange will pass either test. Also, nothing is cracking or chipping in water.

Similar results with 1084, except I used 1/8". Took three strikes to shatter (medium blows with round end of a small peening hammer, not a tap but definitely not getting really into it) but maybe thats because it's twice as thick?

I'm at 8,000 ft above sea level, which I'm really curious if that has anything to do with anything. Have not done the magnet test yet. Will do that tomorrow, but have to buy a magnet first.

I'm not sure if the steel is TOO hot, because anything less bright does not harden. I still have the pieces that shattered, the grain does not look coarse, but I also do not know exactly what I'm looking at.

Thanks ahead of time for any input anyone has to add. Really hoping to get this HT down. Btw, if it matters at all I've been using two propane torches.

[Airborne Steel]

I am definitely no guru, but I'll give you some information as I understand it and has worked for me with 1084. I use peanut oil currently but will be getting proper quench oil very soon.

The flaking is the scale blowing off the hardened part of the blade. This is normal.

After you have normalizes your blade, you should heat the blade until it will no longer attract a magnet (this is only a guesstimate of proper temperature. you actually want about 100 degrees hotter that that. (A side note, I have been told that if you buy some kosher salt, and put a line of it on your blade,when it melts quickly you are at 1500 degrees- the temp you want to quench your 1084 blade at.) (I have read many temps from 1425 when trying for a hamon with clay to 1500 as a target for quenching 1084)

You want to try and hold it at that temp for a bit to make sure its at temp all the way through.

Pull it out of the forge and quench into 120 degree oil, keep the blade moving forward and back but NOT side to side (to prevent warping).

Of course it would be better to KNOW what temp your forge is running at via a thermocouple, I am adding that soon as well.

I'll try to find a link by a Guru for you that is MUCH better and more complete info that I have given you here, however, it is for more advanced equipment. (and more consistent results).

Here is the link from Kevin Cashen's site:
http://www.cashenblades.com/info/steel/1084.html

I hope this helps.
Heat treating is what will make or break a knife. It is the most crucial step.
have fun.

I forgot to mention that the magnet will only work on the way up in temp.
I have read that you have to let the blade cool WAY down before the magnet will re-attract to it. See Kevin's post (#3) in this thread-
http://knifedogs.com/showthread.php?...ghlight=magnet

[Doug Lester]

Ok, if you are getting the steel to shatter then you are forming martensite. As Airborne said, you really need to check the steel with a magnet to be sure that it has austinized but also, as he said, you need to get it just a little hotter and soak the steel for a minute or two. Steel will become non-magnetic just before it austinized. Thats the reason that you need to watch the steel and mark the color when it first becomes non-magnetic and then get it just a shade brighter.

Both 1095 and 1084 are water hardening steel. Do I remember you saying that you got it from Aldo? If you did then the 1095 should harden in a quick oil as should the 1084. What you have to remember is that the steel must be above critical temperature, that is the steel must be hot enough for the austinite to be stable, when it enters the quenchant. This is especially important with something like 1095 or 1084 because the noses of both ITT curves are far to the left and you have less than one second to miss it.

It looks like that you have a handle on the quenching. Now you need to take a blade all the way through tempering and test the edge. Keep up the good work.

Doug

[Ed Tipton]

Cpt-jens...The first thing is that I do agree with using the magnet since determining temp from color is iffy...especially for the in-experienced. The magnet is more absolute...it either is or is not magnetic. With experience in your environment, you may be able to rely on the colors.
Ed Caffrey has repeatedly stated that he no longer uses 1095 due to inconsistancies and imperfections in that particular grade of steel. With that thought in mind, I would suggest you work with only the 1084 until you feel comfortable with being able to do a good/repeatable HT. I have used some 1080 from Kelly Cupples and have found that it gives more consistant results using water for the quench. I think it is important to have a baseline where you are comfortable with the results. Once you have a good feel for the 1084, you can expand your horizons.
The 1084 is about as simple as it gets. You can certainly use a propane torch...but of course...a forge would be better. For knifemaking I definitely recommend a propane forge. A simple toaster oven is sufficient fot tempering 1084.
Your self test is OK since using the destructive testing is really the only way to know what you've got. A really fine grain structure is what you're after. With 1084, the grain should be a very light gray color with no discernable "grains". If the color is darker and you can see the grainy structure of the steel, you're probably getting it too hot. It will still be hard and will shatter when struck, and a file will skate, but if the individual grain is showing it is not nearly as strong as the light gray color.
Hope this helps.

[Eli Jensen]

Thanks so much guys! This gives me great confidence after a really blue day. The piece IS light gray with no visible grain, I feel that if I took it under a dissecting microscope (which I will today) I would barely be able to see grain. And again, I didn't do a magnet test simply because I haven't a magnet, which I will rectify today (homedepot day!).

I did get the 1084 from Aldo, and the 1095 from Jantz. I got the 1095 before I knew much about anything and thought I could do it and was just using it up, experimenting with HTing and grinding and such. But I mean business with the 1084.

I've got a toaster oven and its the weirdest thing. I've been told to use sand to keep the temp around the blade consistent. Well using another thermometer, I've found that its #### consistent! Consistently EXACTLY 75 degrees warmer than the dial says, but the thermometer doesn't waver at all once its set. I don't exactly trust this so will try and track down some sand. I used dirt before, which is just sand with finer structure, but #### that organic matter can stink! So, sand.

And also I was using a torch straight up but am putting together an inexpensive, easy propane forge. Graduating in a year so it doesn't need to last any longer than that, cause I'ma give it away anyways at that point and build a better one.

[Doug Lester]

Home Depot has sand though you might find small bags in the horticultural department even the stuff in building supply is not that expensive.

I don't use 1095 either anymore, what I got was from Admiral, because of quenching problems. The stuff would harden in a brine solution but wouldn't harden in oil. I was at a hammer-in over at Mad Dwarf Forge last year and Aldo Bruno was there with a batch of 1095 he had made up for knife making so the manganese was right. Some of the smiths there did sample pieces and it worked out fine and was giving great hamons. However, I'm not sure if they were quenching in oil or water.

Doug

[Eli Jensen]

I'll keep experimenting with oil and water, and maybe one day brine. But until I get cracking or whatever, water seems like a good option.

[Doug Lester]

There are people who consistantly use water and brine even for steel that one wouldn't necessarily consider water hardening. It's all about what works for you.

Doug

[son_of_bluegras]

One thing I haven't seen mentioned is looking for the decalescence (change is brightness or color as the steel undergoes the phase change), with practice you may see it as you are heating the blade and won't need the magnet.

ron

[Thingmaker]

Originally Posted by Cpt-Jens

Took three strikes to shatter (medium blows with round end of a small peening hammer, not a tap but definitely not getting really into it) but maybe thats because it's twice as thick?

The modulus of rigidity is proportional to the third power of thickness. English translation: If it's twice as thick, it's 8 times as rigid. If it's 3 times as thick, it's 27 times as rigid.

[Eli Jensen]

So I took a go at hardening some knives tonight. All in all it was a good learning experience. Two blades cracked Will have to use oil. One of the ones that did was the one I was really hoping would live. But I'm guessing that means at least I reached the correct temperature. I opened the other that cracked (much to the irritation of my neighbors) and there doesn't appear to be any grain growth.

[Ed Tipton]

Cpt-jens....One thing that can be done to help with the cracking is to eliminate to the greatest extent possible any scratches, burs, cuts or abrasions that could be possible heat stress risers. I typically take my blades to almost a finish grind before quenching. Even using something like 80 grit sanding abrasive can leave stress risers in the steel. I try and remove all pits and everything that looks like it shouldn't be there prior to quenching. Those people who routinely use water for their quench usually do a good job of cleaning up the blade before the quench.
It should be understood that in all probability, your blade will never see more stress during it's lifetime than it does during the quench cycle. Even outright abuse may fall short of the quench stress. I don't think there are many newbies out there who have a good appreciation of the internal stresses that the blade undergoes during the quench cycle, but the quench is a very violent and stressful event where the internal forces acting upon the blade literally are trying to pull itself apart...and all this stress frequently results in either cracks or warping.

[Kostoglotov]

In addition to Ed's comments, when quenching in brine having your grinds even and equal is critical.