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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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Heat Treat Question
I kniow that 1095 is not the easiest steel to heat treat. I am using my propane forge to do this and canola oil. My issue is that I am getting a lot of scale. Is this normal or am I heating the steel to hot. I know that it is not magnetic but I cannot tell what the temperature is. Any suggestions?
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#2
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This is not an easy one. It will depend on where you got your 1095 from. If you got it from The New Jersey Steel baron it will have a good level of manganese in it an will harden in oil. If not the manganese level may be low enough that you will have to use water or brine to quench in. Regardless, you will have to get the steel non-magnetic, a little hotter actually, and hold it there for a few minutes or the iron crystals in the steel will not change phase and if it doesn't change phase you cannot quench harden it.
The scale is coming from all the air inside the forge. Being that you are using a propane torch to heat your forge with that may just be something that you'll have to live with until you can get some other type of burner on your forge. Just keep the scale brushed off or it can be pounded into your work. Doug __________________ If you're not making mistakes then you're not trying hard enough |
#3
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Not sure that I'm "reading" torch in his post, but regardless it is an oxygen rich environment. Most likely combined with too high a heat.
Could boil down to actual forge design. Can you post a pic of your forge in operation? Can you control your temp in your forge? Do you have a means other than a magnet to check the temp of your forge & blade? What are the dimensions of your blade to be HTd? Answer the questions above as best you can and we can better help you figure things out. Non mag is just an indicator that you are getting near the right temp for your steel. You have to catch the change to non mag on the way up in temp, not accurate once you pass that point. 1095 is a good bit more tempermental about thermal cycling and as Doug indicated has a fairly wide range in composition, making it very tricky for the novice. Consider switching to 1084/1080 to learn the game. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
#4
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To answer some of your questions...
1. The forge retangular. The inside opening is 16 inches long, 4 inches wide, and 4 inches tall. 2. The forge has a blower motor and the burner coming in from the left side. 3. I am using a lead pipe in the forge to help treat more evenly. 4. You can control the heat by controling the amount of fuel coming from the tank. It has a seperate flow control. 5. You can control the amount of air going throug the burner. 6. The deminsions of the blades have varied but most are 8 to 9 inches long and 1 1/2 inches wide. 1095 came from NJ Steel Baron. 7. I do not have anything else to test the temperature. I would open to suggestions. Thanks for all the responses. You guys are great! Tony |
#5
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Very hard to gain even heat control well enough for heattreatment with the forge configuration you have described. 4x4x16 is a pretty long chamber for one torch. Is the entire chamber getting the same interior color once up to working heat? If one area is brighter that's your hot spot. If you are getting excessive scaling using the interior secondary pipe (black pipe instead of lead, I hope, as lead melts at just over 600*F), then it sounds like you are running the forge way too hot. Pics of the forge running would be helpful. Forced air burners are a bit harder to get tuned down for temps necessary for heattreating. The interior pipe will help a lot, but still getting her to regulate that low takes some refined tweaking. Find someone with a good pyrometer and check all areas of the forge at the settings you think are right then work from there.
The non magnetic observation will work pretty well if you have very good color preception. As the blade heats up and begins to become nonmag take close note of it's color. Your thinner portions at your tapers (point & edge) will already be a good bit hotter and brighter than the area becoming nomag. That's the color you want the whole blade to be before quench, but not any brighter. If you have very good control of the heat in your forge you should be able to adjust the interior to match this color. If you can do that then, when the entire blade matches the forge interior you know you are on your mark. You really have to pay very close attention to this or you will get enlarged grain growth and possible decarb of your thinner parts. This takes a good deal of practice and concentration. Once done test you blades extensively, they will tell the tale. No problems with the steel considering the source, but as mentioned before 1095 does not take well to overheating. I'm guessing from your moniker that you are in NC. What part? Lots of good bladesmiths in NC, may can hook you up with someone that can show you what I'm talking about. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H Last edited by Crex; 12-08-2013 at 04:47 PM. |
#6
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Carl, thanks for the info. I am ordering a pyrometer tomorrow.I am near Charlotte, NC. On the NC/SC border. Thanks to everyone! Great information. I am a true newby and I have a lot to learn.
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#7
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Ya, what Carl said. I have a forge built in a mailbox that has about those same dimensions but round(ish) with a flat floor. To be honest I use it less and less for both forging and heat treating. I have a smaller forge that has a heat chamber 7" long with a 4" diameter and I can heat treat a 7-8" blade in it just fine.
Two things that you can do. Cut back on the gas and air flow and run your forge where the flame coming out is a little orange indicating combustion outside the fire chamber. The other is to put a cap on that black pipe and when you heat the blade for heat treating toss a couple of pieces of wood into it to burn off free oxygen. One thing to watch on the pyrometers that I had problems with is that all that I ran across had themocouples that weren't rated for the temperatures that we deal with. So you may have a pyrometer that can register temperatures in the range that you want to deal with but the thermocouple will be burned up. I always have had to order a ceramic shielded themocouple separately. I found that the best source was Ebay. Sorry about the propane torch thing. I shouldn't post late at night. Doug __________________ If you're not making mistakes then you're not trying hard enough |
#8
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Tony, you might want to check in with the NC Knifemakers' Guild. They have a sub forum further down in the KNF. They have a really nice organization and are a fine group of folks to affiliate with. Their Guild is a teaching/sharing guild like ours here in GA. You do not have to be an accomplished maker to be a member. The networking and information one can access is priceless, much the same as here on KNF, but face to face and hands on. Highly recommend checking them out.
I also conduct an open Hammer-in in Blairsville, GA twice a year that you are more than welcome to attend and participate. The next one will be #27 and will be on the last weekend in March, 2014. Watch for the formal announcement under the heading "Trackrock Hammer-in" here and on the GA Knifemakers' Guild forum further down. Lots of hands on stuff for those that attend - bring a kid. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
#9
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Carl, I am a member of the guild. Thanks for the heads up on that. It is a very good organization. I would love to come to your "hammer in". What is a "hammer in" and where is Blair Ga? I will mark my calendar.
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#10
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Blairsville is in North GA between Hiawassee and Blue Ridge on Hwy 515/76.
Hammer-in is just what it sounds like.....bunch of folks get together and pound steel into cutlery. (little more to it than that, but that's the gist of it) Check out some of the photo links up at the top of KNF posted by Randy Scott, plus you can google Trackrock Hammer-in and find several past threads about it. __________________ Carl Rechsteiner, Bladesmith Georgia Custom Knifemakers Guild, Charter Member Knifemakers Guild, voting member Registered Master Artist - GA Council for the Arts C Rex Custom Knives Blade Show Table 6-H |
Tags |
1084, 1095, blade, blades, blower, cutlery, design, easy, edge, forge, forging, hammer, harden, heat, heat treat, hot, iron, knife, making, motor, post, scale, steel |
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