MetalMuncher Posted January 19, 2009 Share Posted January 19, 2009 Greetings all! I know guys, this has been covered quite alot and I'm sure you are weary in well doing. But just tell me when I go wrong. What I do for my 5160 steel is this: Forge it to the proper shape, and anneal. I then grind and move on to HT. So far so good right? Now here is where I know I'm missing something. I then heat the piece to cherry and let it cool in still air untill it looses its color, I do this three times(normalizing). I re-heat to cherry(critical) and quench in warm motor oil. I then temper for 20 min. at 230 C. Anything I missed? Too much grain growth? Any help is more than welcome. Thanks dudes!:D Quote Link to comment Share on other sites More sharing options...
Graham Fredeen Posted January 19, 2009 Share Posted January 19, 2009 Some of the HT depends on what you are making (the temper cycle to be specific). Your steps leading up through the hardening are fine (but with normalization I let it air cool quite a bit past just loosing its color). The only thing I can see is your tempering might be off (again depends on what you are HTing). If you are doing a knife, 230 C is a bit too high. For knives you want to be somewhere in the 350-400 F (175-200 C) range. A sword will be higher (about where you mentioned). And these temp ranges won't be the same for other things you might be making (chisels, springs, etc). Be sure to research what tempering temps are necessary for your particular item. And I would recomend tempering for quite a bit longer than 20min. I usually do 2 temper cycles at about an hour a piece. 2 hours tempering might not be completly necessary, but I wouldn't go much below 1 hour. Quote Link to comment Share on other sites More sharing options...
viking-sword Posted January 19, 2009 Share Posted January 19, 2009 (edited) You didn't mention what type of problems you were having with this method of HT as far end results, but I can Imagine what they might be. For starters, anytime you anneal, normalize, or quench for the hardening process, you must know what temp you are at each time ,as going by color alone is way too much of an uncertainty,and using a magnet is a much more certain way of knowing what temp you are at, you didn't mention one so I assumed you went by color alone. Another important consideration is the viscosity and temp of your quenching oil so you know if you have a fast or slow quench medium, generally 120 to 150F degrees is good and will give a proper hardness. Finally, when you temper the blade back the most accepted and successful formula is to temper at the proper temp three times for a length of at least two hours each time, allowing it to cool to room temp between sessions. For 5160 I temper at 350 to 400F degrees minimum, and this will give me a good tough edge that will not chip out during use. I'm sure many others will chime in with good advise, but if you need more info , please feel free to ask. Wes Edited January 19, 2009 by viking-sword Quote Link to comment Share on other sites More sharing options...
MetalMuncher Posted January 20, 2009 Author Share Posted January 20, 2009 Hello! TarAlderian nice to have you around, I'm making knives, I probably should have mentioned that. I thought my temper was too high...So, cooling until it looses its color isnt enough? Untill what temp do you cool? I'm not having problems viking-sword, I just want perfection in my blades. So I need to work on my tempering....shouldnt be hard. I should also incorporate magnents into my work, I wasnt at first because I didnt think it was necessary. Thanks for your patience! Much appreciated. Quote Link to comment Share on other sites More sharing options...
Guest mod07 Posted January 20, 2009 Share Posted January 20, 2009 relocated due to this being a blade topic, not a general smithing issue. Quote Link to comment Share on other sites More sharing options...
Graham Fredeen Posted January 20, 2009 Share Posted January 20, 2009 With normalization I run 3 step down cycles, stepping down the temp gradually with each cycle (First at (maybe a hair above)cirtical, second at critical, third slightly below). After I pull the blade from the forge I pretty much let it cool down all the way to room temp (at least to the point where I can grab it barehanded) before going back into the forge for the next cycle. I also straighten the blade out in between these steps if it needs it. I don't want to set a hot blade on the anvil or in the vice because it will cause uneven rates of cooling, which is something you try to avoid with normalization. I usually HT multiple blades at a time, so while one or two are out cooling, the next is being heated so I don't waste excess fuel. A magnet is not "necessary" to judge temps if you are comfortable enough judging by eye. The only problem is that you have to have consistancy in your lighting in order to do this. If you HT in pure sunlight, indirect sunlight, shade, dim shop light, moonlight, or pure darkness the color of the steel will appear drastically different at the same temp in these different conditions. This is why a magnet is a good idea. Even if you are great at judging temps by eye, it doesnt hurt to double check with a magnet instead of risking a perfectly good blade. The magnet will also help you to get a feel for what critical temp looks like in different lighting conditions. Idealy a thermocouple or pyrometer is the best method to know the exact temp of your blade, but if thats not in your budget a magnet is the next best thing. The tempering temps depend heavily on what type of blade you have made and what type of uses it will see. A short blade for cutting that wont see as much stress as a big blade will be tempered lower (350F) a larger knife that might be used for chopping and will see more stress should be tempered at higher temps (400 F). A sword, depending on length, will required even higher temps (450-500 F). A good test to see if your temper is right is after tempering, sharpen the blade, then clamp a brass rod in a vice and lay the edge on it and apply pressure on the edge to flex it. If the edge chips out you know you need to temper a little more. Increase the temp run another cycle and test again. If the edge folds or rolls over on itself you know you have tempered too hot. Unfortunately if you do that the only solution is to re-normalize, re-harden, and re-temper. You will know a good edge as it should flex on the brass rod and return back to its shape without chipping or folding. Tempering times are highly debatable. Some argue only an hour, some two, some a lot longer. Tempering longer will not hurt the blade at all (only going too hot in the temper will cut blade performance). I would say an hour is the minimum time you would want to go, but longer is definately better. I usually run a minimum of 2 cycles at an hour a piece, and straighten any warps or bends in between. But more often that not I will run a couple more just for good measure. Some steels will want more time than others and the method suggested by viking-sword will ensure no problems. Another thing I would recomend when you are trying to perfect heat treating is to make a few blades just for destruction. I know it seems like a waste to destroy hard work, but in the long run its worth it to really see what is working and where you might be going wrong. Make a knife blade, HT it, test different tempering temps, then take the blade to destruction. Chop up some lumber, cut some rope, etc and see what the edge has done (chipped, rolled, still sharp etc) Then do blade flex tests to see how far you can flex the blade before fracture (be careful doing this. Use full face shield, heavy leather apron, gloves, etc. Dont want fragments of blade to get you). Once the blade breaks inspect the grain of the steel. See what the problems you ran into were (large grain, little flex, soft edge, or whatever it might be) adjust your HT methods and test another. Do it until you get it right. This will tell you huge amounts about the quality of your HT and will help you to perfect it for a particular steel. Additionally you will know if future blades HT with the same method will perform to your standards. Once you have the HT down you can really start to work on the other aspects of knife and blade making. Its pointless to make a nice looking knife if it will not perform sufficiently. My belief is function first then astetics. Its also good to do a destruction test on a blade every now and then anyways to ensure that you are keeping your quality up, and if you start messing around with new steels and need to work out bugs in HT, destruction testing is a good idea too. Quote Link to comment Share on other sites More sharing options...
Canska Posted January 20, 2009 Share Posted January 20, 2009 Another thing I would recomend when you are trying to perfect heat treating is to make a few blades just for destruction. I know it seems like a waste to destroy hard work, but in the long run its worth it to really see what is working and where you might be going wrong. I'll second that. I still do destructive testing every time I try a new type of steel. There's no better way to know you've treated it properly than putting it to the test. Quote Link to comment Share on other sites More sharing options...
J Anderson R Posted January 21, 2009 Share Posted January 21, 2009 If your looking to add some good qualities to the steel I would recomend, since your using 5160, is to try a triple edge quench following each hardening cycle with a 24 hour freeze cycle between hardenings ( your home freezer will work for this ). Then, after the 3rd freeze, temper as usual. I was amazed by the added strength and grain refinement on my first triple hardened 5160 blade, its worth trying. Check out Ed Fowlers dvds, great info on high performance bladesmithing. Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted January 21, 2009 Share Posted January 21, 2009 Good place to start is with some more research. Bp0078 is full of information and I suggest to either check out books from the library on blade making or even better is to add them to your library. Any information from Jim Hrousalas has been helpfull to me. I know this makes the quest for info cause you to do more. But to be honest the information anyone can type in response to a good question such as yours is too lenghty to type in this space Quote Link to comment Share on other sites More sharing options...
wildmanz Posted January 23, 2009 Share Posted January 23, 2009 this is my first message hi-after tempering i drop the unfinished knife on the shop floor point first that tells the story 2 hard or 2 soft Wildmanz Quote Link to comment Share on other sites More sharing options...
MetalMuncher Posted January 23, 2009 Author Share Posted January 23, 2009 Thanks everyone! Thanks for your patience TarAlderian, lots of great stuff. Ht should run more smoothly now! Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted January 23, 2009 Share Posted January 23, 2009 this is my first message hi-after tempering i drop the unfinished knife on the shop floor point first that tells the story 2 hard or 2 soft Wildmanz Do you really think that is the best way to test? If it was too soft, after straightening you can re do the heat treat, but if too hard, and it shatters, you have no way for fix it as its ruined? There are other methods mentioned at the start, and throughout this section, please read them, and save yourself a little heartache. Quote Link to comment Share on other sites More sharing options...
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