overmodulated Posted October 18, 2009 Share Posted October 18, 2009 I quenched an O-1 blade in peanut oil and noticed a strange pattern on the surface of the blade. The pattern looks like veins that are slightly raised on the surface. This was very difficult to photograph but I do have photos to share; however the site is giving me an error message with the picture upload at this time. Would anyone know what this means,and whether I somehow ruined the blade? (My first time dealing with O-1). Thanks for any insight you can provide. Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted October 18, 2009 Share Posted October 18, 2009 There are a lot of things that can go wrong in heat treat. I would not venture a guess about this. If you filled in the blanks a bit it may help: Was the blade forged or ground? what was the surface like when you quenched it? how hot was the blade and the oil at that time? How did you temper after hardening? and at what temp? did you do a bend test or in some other way try and figure out the hardness after tempering? One of my suggestions I offer to everyone starting is to begin with rather simple 10xx steels and stay with them for a long time until you get this all worked out and do destructive and cutting test on blades at a regular interval. This way you can try a few different things now and then and see wot each of them does to a blade. a steel I like for this is 1084..lots of folks suggest 5160, either one will work well but just syay with one for quite a while. I would also like to know if you are sure this is 0-1? If it is and you purchased it from a reputable company they may offer some ideas if you ship it to them. Quote Link to comment Share on other sites More sharing options...
thecelticforge Posted October 18, 2009 Share Posted October 18, 2009 Can these veins be polished off? I seem to remember the same thing happening in lard also. Quote Link to comment Share on other sites More sharing options...
markb Posted October 18, 2009 Share Posted October 18, 2009 I have noticed a pattern in a 1084 knife I made and it didn't polish out. Here's a possable solution Quote Kevin R. Cashen: I often get phone calls from makers wondering what they did wrong with a hypereutectoid steel that has extra carbide forming elements. They get an odd damascus like pattern all over the blade. I tell them to soak longer or raise the temperature before the quench to dissolve those extra carbides and alloy banding and the problem will go away. The quote is in the text here:Heat treating 1084 Steel Hpe this is helpful Quote Link to comment Share on other sites More sharing options...
overmodulated Posted October 18, 2009 Author Share Posted October 18, 2009 thanks. the site's still not letting me upload .jpgs that are just ~ 150KB. I bought the O-1 from texas knifemaking supplies, which I regard a reputable source. Have pounded out many 5160 and 10XX blades before this one, which was also my first ground blade (no forging). It was perfectly flat when received but before heat treating I belt-sanded away the lines (like grain in wood) that ran parallel with the blank to make it much smoother. Soak time was about 5 min at a mid-range orange - to my eyes it was bright, but I feared burning it and used judgement based on work with other steels. The peanut oil was warm to the touch by plunging a couple of heated pieces of mild steel into it. The so-called veins look like a large granular structure. Damascus-type pattern is a good way to explain it, but it was all uniform color. I could probably sand them away. I did not normalize, nor did I temper it back, but tried to remove the blade from the oil at the right time to retain enough heat to let that work on itself for a little softening (the blade re-ignited when removed from the oil and was left to cool.) File test confirms the plunge was fast enough to achieve good hardness. Wish I could affix the pics. thanks agin folks Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted October 18, 2009 Share Posted October 18, 2009 "Removing from the oil at the right time" is not the same as tempering. You cannot get a "temper" until after it has cooled to room temperature. If you understand TTT or ITC curves you'll see why this is true. In hardening, the part must get down to 800 or so at a rapid rate, but from there on down it can cool rather slowly and still be "full hard". Your interrupted quench is doing nothing to draw the temper and is fully hard. Not to be confused with "one-heat" quench and temper like on a chisel or hammer where just the end is quenched to cold and then residual heat in the upper part of the tool is used to draw the end. Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted October 18, 2009 Share Posted October 18, 2009 (edited) It sounds to me like you may have gotten too hot before quench. So I would choose one option from two that come to mind. Normalize three times and try and reduce the grain size. then harden and temper after letting heat drop Like said above...However that will not tell you what you have right now and will not assure you that my guess is right. Second choice I would do. I would wear all the protection I need and put it in a vise, smack it with a big hammer and look at the grain structure. If it is large then consider that blade part of your tuition. If it is nice and tiny then I just gave you a poor choice. Now,,how do you know wot size is large and wot is tiny. Only way I know is by making blades ,,heat treat them and breaking and looking. And to back up to my prior post this is where making a lot of blades from the same kind of steel pays off. Break them, mark them and keep records..of what the steel was and everything you did to them prior to the break. I know this just sounds like too much work for anyone that does just a few blades now and then but this is how you make good working blades. How you finish, how you sharpen, whether you grind or forge is all after getting this part right. A 6 foot bar of steel will let you do a lot of this and that cost is not out of sight for research. Remember you do not have to finish a blade to test, but I do hollow grind mine for this,,,And remember you can get injured so protect your self. Your ready to step up a notch if you wish. Edited October 18, 2009 by Rich Hale Quote Link to comment Share on other sites More sharing options...
overmodulated Posted October 19, 2009 Author Share Posted October 19, 2009 yes I have some experimenting to do with this steel. to answer a couple of questions and points raised: I'd like to normalize but I read that the max temp needs to be reduced each heat cycle otherwise it can work against you, and increase grain size. My inability to judge slight temp reductions by eyesight shyed me away from this approach (normalization). If it is fine to just heat the thing past magnetic each time then fine, but I heard there was something more critical about the temp it needs to reach time (maybe from you Rich?) Nakedanvil: you mentioned "the part must get down to 800 or so at a rapid rate, but from there on down it can cool rather slowly.." This is exactly what I was trying to achieve by removing the blade from the oil at the "right time". Not sure what the flash point is of peanut oil, but I was hoping that the blade was up in the vicinity of 800 degrees when the oil flared back up upon removal from the bin. thanks again for the feedback Quote Link to comment Share on other sites More sharing options...
MattBower Posted October 19, 2009 Share Posted October 19, 2009 Overmod, "This is exactly what I was trying to achieve by removing the blade from the oil at the 'right time'." That's fine, as long as you realize that this doesn't result in tempering (or at least not much, depending on your steel). After this process you have basically a full hard blade, which you then need to go back and temper. As far as what's causing the "activity" you're seeing, I thought I had posted something in this thread about carbide banding, but I guess I'm getting senile. (And I'm not even 40!) Check out this thread and see if it looks familiar. Dendritic Steel - Bladesmith's Forum Board Yes, normalizing should be done at decreasing temperatures to refine grain size. If you don't trust yourself to judge it by eye, think about purchasing some Tempilaq. (Tempilstiks would work, too, but I find Tempilaq easier to work with.) 1600, 1500 and 1450 would do. Paint the blade with 1600 Tempilaq and heat just until the lacquer melts. Let the blade air cool to room temp. (Or if you're in a hurry, let it air cool way into the black range, then quench.) Repaint with 1500 and repeat. Repaint with 1450 and let cool to room temp. Good to go. Quote Link to comment Share on other sites More sharing options...
viking-sword Posted November 14, 2009 Share Posted November 14, 2009 Also too add to all this info, O1 specifically needs to soak at critical temp for 30 min to get all the steel into solution for a complete hardening. Wes Quote Link to comment Share on other sites More sharing options...
MattBower Posted November 18, 2009 Share Posted November 18, 2009 Yes, O1 isn't an ideal steel for relatively primitive, backyard heat treating methods. Quote Link to comment Share on other sites More sharing options...
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