I got stuck as the heat treater at my last job because I simply mentioned that I made knives to the owner. So whenever a HT job came up I was pressed into service. They had a gas stove next to their 24 inch deep HT oven for tempering to 600 degrees. Their HT oven was slow to heat up too. I also used Hinderliter Heat Treat in OKC, OK who I was familiar with from my early days making knives, they were a wealth of knowledge and help. Hinderliter told me to set the temp at 1850 since the oven was so slow as the worst thing you can do heat treating D2 is overheat it. Then hold for only 20 minutes instead of 30 once I reached 1850. It worked great and I used an air blast with an air nozzle for the quench. I immediately once they reached room temp put the parts in the oven then up to 500 degrees for two hours. First temper, second temper was 1000 degrees in the HT oven for 30 minutes at top the air cool. HRC59-60 every time as we had a Rockwell tester. edit; I forgot to mention that I would punch a hole in the foil on one end and snatch them out with hooks I made from 1/8th inch weld rod.
I've heard that in a few places as well. It's not an option for me, as I only have one oven available. I asked the two guys that have been helping me along the way - probably 70 years of experience making knives between them - and this is the way they do it. I have not had a problem with this method.
instead of wood shavings try JUST Exhaling into the stainless steel bag you made , I have heat treated doing this for years with great success , Exhale into the bag 2-3 times before closing . parts come out with a straw marbling color
It's not an option for me, as I only have one oven available. I asked the two guys that have been helping me along the way - probably 70 years of experience making knives between them - and this is the way they do it. I have not had a problem with this method.
at the end of the video, you say your going to temper them at 475. is this the same process again, but at 475 instead of the higher temp? inside new foils? use the same foils?
I noticed you do not remove the foil before plate quenching.. Others do.. What reasons are there for doing or not doing this. I know there is a time issue to deal with whenever removing foil. Also, many steels require a very specific soak time.. With all blades ready at the same time and having to wait for each blade to be quenched it seems they would all have different soak periods. How is this dealt with..Is there a way to edge quench stainless? Thanks and nice video
I don't remove the foil because it would significantly reduce the temperature before plate quenching and not give the hardness I want. The soak time is based on thickness of the material and is to ensure that the steel is up to temp. Letting it soak a little longer does not change things.
The ease or difficulty in sharpening various steels depends a lot on the heat treatment. When I make them I use my belt sander to sharpen them. I don't recommend that unless you practice, as it is easy to ruin a knife with power tools. D2 is a wear resistant steel, but I have used sharpening stones and achieved very good results.
I don't think I would attempt to heat treat an air cooled steel in a coal fire. Any of the knife making suppliers should be able to offer you a choice of steels.
CrashbladeKnives Thanks for the advice. I found on online company that offers (what I assume) heat treated blanks which would get me a heckuva lot closer to a finished knife. But I figured I'd go with a more high end steel like CPM S110V because I'm going for edge retention. I enjoy watching you videos tho, you make some very beautiful pieces
I notice you temper the steel within stage 2 tempering range (475-500 F), D2 is normally triple tempered at over 1,000 F for proper secondary carbide precipitation, which is better for edge retention and toughness. My question is, have you had any problems with these blades braking during hard use like battoning? It appears the knives have a full tang, which helps, but with 155 points carbon D2 is not really tough to begin with. By the way, that is a really nice oven, wish I had one as nice. Regards.
+Rafael Lastra I have had my D2 heat treatment tested with Rockwell Hardness testers and the results are exactly where I want them. D2 is a lot tougher than you give it credit for.
+Rafael Lastra Compaired with other steels of course D2 isn't "that tough" But it's darn tough enough unless someone is being an idiot. Cryogenics from my experience is key here. I use D2 a bit and they are tough knives, no toughness like my 1075 and SUP9 blades but they're still tough. Zu Blade works also uses D2 in their tactical knives with great success. But the sounds of things if the D2 you have been working with hasn't been "tough" the heat treatment has been botched. It's all relative though and there are many other factors.
Scott Birse In general terms, the more carbon a steel has the harder/stronger and more wear resistant it can become. The trade off is that when you increase carbon and consequently strength toughness decreases. So you have to trade off hardness with toughness for a given application, i.e. knife, gun, machine member, etc... Steels begin at 0.07% carbon (very mild steel) all the way up to around 1.75% which are only used in very specific applications where requrements for touhness (ability to take a beating without cracking) are very, very low. D2 has 1.55% carbon and over 12% Chrome, among other alloy elements. The carbon content is waayyyy high, this leads to outstanding edge retention but toughness of D2 is close to nothing. Battoning with a survival knife made out of D2 will simply snap the blade in two making survival difficult at best. D2 has a place in knives but it better suited to a skinner where you do not want to be sharpening the knife every 10 minutes and toughness requirements are low. The reason I bring up the question of tempering temperature is that if you use D2 for a knife the best tempering practice is triple temper above 1,000 degrees (F), which gives the steel the best toughness it can obtain, it is still low mind you but it is the best D2 can muster. If you are asking why, the reason is that so with so much carbon the steel will have retained austenite in the microstructure which is nothing more than a fancy way of saying part of the steel is not allowed to make the transformation to the hardened state because the high level of carbon around these untransformed pockets do harden and effectively lock the pocket in position. The material (austenite) wants to harden but it´s surrounding has ¨frozen¨ it in a position where it cannot move and movement is necessary to harden. The problem is that these pockets of retained austenite will transform to hardened steel with time and/or use as a result of stresses and temperature changes. When this happens you end up with newly created martensite (hardened steel). The problem is that this pocket of now fully hard material is not tempered, and as we know steel cannot be put into service without tempering as it is glass hard and will crack easily. So you take a knife where this has happened and use it on a cold winter day (where steel toughness is even lower) and use it to batton some lumber which puts bending stresses on the material and SNAP, the knife breaks as a result of a crack that propagated from one of these pockets of untempered steel. The reason these steels are triple tempered at high temperatures is to give these pockets the chance to convert properly. By heating them up to over 1000 degrees (F) the atoms loosen up and separate a bit, that is why steel expands when heated, so the ¨frozen¨ state the pocket finds itself in loosens it´s grip, so to speak, and converts to fresh, hardened steel. The second temper is to temper the hardened steel created during the first temper and the third temper is a safety temper in the event there was still some lingering un-tempered steel. In general, the higher the carbon content the more retained austenite will exist in pockets and with D2 you need to maximize toughness. Sorry for being long winded but I was not sure what part of my original question you were referring to, so I let you have the whole thing. Regards.
That might be the reason why the oven takes long to get hot,cause u have to much in it at one time. Its like a micowave? When u cook two hot pockets it takes longer to cook than just cooking one. That could be it
Some steels are liquid quenched while others are air quenched. This steel needs to be air quenched. Steels that should be liquid quenched will not turn out well with this method.
well crap I wish I would have watched this before ordering some be too. I'm using a charcoal Forge. What are the repercussions of not heat treating in airtight environment?
A steel like D2 is not really meant to be heat treated in a coal forge. I know a few people that have tried it and did not get very good results. You may want to send your D2 out for heat treating.
I tried that too, but mine was pure coal as opposed to charcoal. I went with the heat and quench method, quenching in used motor oil. Blade turned out pretty well, according to the user. I will reproduce the process when I get home in a month's time, and update you accordingly.
+Crashbladeknives Hello my friend new subscriber. Do you have a website to sell you're knives and prices. Also do you do Stainless steel knives. thanks
I use a 2X72 belt sander and haven't used a file to make a knife, but once annealed it shouldn't be any more difficult to work than other annealed metals.
For liquid quenching steels that is fine, but for air cooled steels the method described in the vid is a must to prevent decarbuerization and other surface reactions.
+bill65761 Use Lucifer furnaces at work to heat ingots for rolling, not sure if they make smaller ones, but even when the power went out the other day it only dropped about 40degrees c if even
