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Heat Treating and Metallurgy Discussion of heat treatment and metallurgy in knife making. |
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Heat Treating My First Blade. Questions.
Heat Treating my first Blade, 01 Tool Steel. 1. According to the info from Starrett,
Hardening 1450 - 1500 degrees. To achieve an RC of 58/60 temper at 400 - 450 degrees, One hour. 1. How long should the knife soak at 1450 - 1500 degrees? 2. When I Quench the knife in 125 - 150 degrees oil, can I just submerge the blade and part of the tang? Or does the entire knife need to be submerged in the oil? How long should the blade be submerged in the oil? 3. After the quenching and the blade has cooled . I plan on putting it in a preheated Oven at 450 degrees for an hour. How should the blade be cooled after the first tempering, Let it sit till it reaches room tempature or does it get put in the oil again? 4. After the final tempering how could I test the hardness without an RC tester? Thanks for any info on Heat Treating 01 Tool steel. Tim Last edited by Tbonz; 11-14-2004 at 12:31 PM. |
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You can't test hardnes [numbers] without a hardness tester but you can do a file test to make sure ,it shouldn't bite in. When you quench put the blade in but not the tang, when it has reached the temperature of the oil immediately temper. If you want temper a second time [recommended for O-1] just let it cool in air to room temperature then temper again. Soak for 10-15 minutes.
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#3
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01 tool steel
Thanks for the reply mete.
I Heat Treated my first knives yesterday. My first attempt at heat treating a knife made of 01 Tool Steel did not come out. Can I Heat Treat it again? My 2nd attempt was with a knife made of 154 CM and this time it worked. I credit this to the information provided on another thread. I tempered it twice at 450 degrees for an hour each time. I'm hoping I ended up with a blade with an hardness of about 58 - 59 RC. I did the file test and it slid along the surface. Last edited by Tbonz; 11-15-2004 at 07:04 AM. |
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I believe you should be able to heat treat the O1 again with acceptable results.
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#6
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I am experiencing my best soak time for O1 at about 9 minutes. That is about 9 minutes after the blade has equalized - became the same temperature throughout its thickness. If your equipment permits bring your blade up moderately to 1200 F and hold there for about 7 minutes, then ramp as quickly as your equipment provides to about 1475 F and soak there for about 9 minutes. Quench IMMEDIATELY and for long enough that it barely smokes when pulled from quench oil. If still too warm return to quench for a few more seconds. Allow to still air cool to NO LESS than hand warm (125 to no greater than 150 F). Place IMMEDIATELY into PREHEATED tempering oven. Temper a minimum of 1 hour at 400 F. Allow to still air cool to room temperature. Repeat temper at 375 F / 1 hour. Edge the blade and test for chipping by chopping hardwood and twisting edge while in the hardwood. If a running of the finger nail detects chips temper again a few degrees higher and repeat testing. A maximum of about 425 - 440 F temper should be all that is required but be sure your tempers are a minimum of one hour per. If you find you can not get good edge retension without tempering at least as high as 400 F (the absolute minimum you should want for your primary temper) you have misperformed an earlier part of the heat treat. Upon raising temper as high as about 440 F and you continue to get edge chipping you may have either over soaked (that is the time at austenitizing temperature - the 1475 F mentioned above) or the soak temperature was too high. If no or little edge chipping but edge retension (sharpness) is poor you may have soaked at too low a temperature or for not long enough.
RL Last edited by rlinger; 11-28-2004 at 04:47 AM. |
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Tim,
I'm a newbie also, but I'll quote two of the fine members here who've been great help to me (whether they knew it or not!) Quote:
Quote:
-Ben |
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As an example, here is one I most recently did. It is O1, 1/4 inch maximum spine thickness. Heat treated as I described above in my first posting except that it was given a cryogenic treatment after a snap temper of 320 F / 45 minutes and the tempering was twice with the first temper being at 410 F / 1 hour. The second or last temper was at 430 F / 1 hour. The resulting tested Rockwell hardness is 59.5 - 60 HRc.
Here is another, but with no cryogenic treatment: Same as described in my above posting except that it was triple tempered. First temper: 400 F / 1hour. Second temper: 420 F / 1 hour. - 60 HRc after second temper. Third temper: 400 F / 1 hour. Resulting tested Rockwell of 59 HRc. That blade was 6 1/4 inch long, 1/4 inch thick O1 with no distal taper. Concentrate on proper soak temperature and proper time at your particular soak temperature and on quickness into quench, how long in quench, getting into preheated temper immediately upon acheiving hand warm, and at least one of your two or three tempers being at a minimum 400 F. Colors are nice and I do like seeing that straw gold. Blues and purples out of tempering are nasty to us when tempering simple carbon steels. Rather than depending on color, depend on good oven thermometers and time in temper. Going by color alone can be misleading. If you see blues and/or purples though caused by tempering your thermometer is broke. RL Last edited by rlinger; 11-29-2004 at 04:00 AM. |
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