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Hi All,
what do you experiences, what is the ideal quenching temperature for K720 or O2 steel to make razor? I have tried from 790 C (tempering 2x180 C). Not bad but a little bit soft and the edge is sensitive. Shaving well but maybe there is a better solution.
I made braking tests and saw this steel has bigger grain sizes than O1. This is the reason why I choosed the lowest temperature.
Thanks in advance for your help!
Bruno uses O2 a lot and may be able to add some useful info.
I use O1 but my HT is 815C into 60c canola oil then 2 X 205C temp cycles
No true HT tester but my RC files tell me it is in the 60RC range
I get my O2 from Bruno & was told to HT just as O1. It's worked fine for me.
I HT by color & gas. Bruno is the guru on O2, Mike Blue may chime in too...you will never go wrong listening to either.
Thank you guys for the quick answers. All information useful to me. I am waiting for the gurus. :)
http://www.cashenblades.com/steel/o1.html
I look at this guys site from time to time, good smith. Here is his info on O-1, IMO it's spot on for O-2. I use Parks 50 for my quench:
O1 is one of the most commonly available tool steels and has been an industry standard for many decades. It possesses a high dimensional stability during heat treatment and is not particularly vulnerable to decarburization. O1 is a fairly deep hardening steel when quenched in oil and it is for this reason that it has too often been incorrectly recommended as a good beginner steel for knifemakers. While it will harden very easily, it is a richer alloy that requires more involved heating and soak times to unlock its full potential in the hardening operation. O1 can cost as much as three times the price as a simple high carbon blade steel which can easily reach their full potential in heat treatment with the simpler equipment most bladesmiths possess, thus making it the less economically prudent choice for many bladesmiths. If you have only a forge to heat treat with why pay extra for a steel that you may not get 100% out of? If however you have the equipment to soak at precise temperature for extended periods, O1 will most likely outperform any of the simpler steels in cutting applications.
Recommended Working Sequence For O1
Forging: Start forging at 1800 to 1950 °F (980 to 1065 °C). Do not forge below 1550 °F (845 °C)
Normalizing: Heat to 1600 °F (870 °C). cool from temperature in still air.
Annealing: Heat to 1400 to 1450 °F (760 to 790 °C). Use lower temperature for small sections and higher tem*perature for large sections. Cool at a maximum rate of 40 °F (22 °C) per hour. The maximum rate is not critical after cooling to below 1000 °F (540 °C). Typical annealed hardness, 183 to 212 HB
Grinding or Machining
Stress Relieving (optional): Heat to 1200 to 1250 °F (620 to 650 °C) Cool in air
Hardening: Aus*tenitize at 1450 to 1500 °F (790 to 815 °C) for 10 to 30 min, then quench in oil. Quenched hardness, 63 to 65 HRC
Tempering: Temper at 350 to 500 °F (175 to 260 °C)
Polish
The following tempering guidelines apply to O1 that has been soaked at temperature for a proper amount of time to achieve maximum hardness. Knifemakers using other methods will have to adjust the resulting hardness numbers downward for the same temperatures.
Tempering Temperature Rockwell Hardness
oC oF HRC
149 300 65
177 350 64-65
204 400 62-63
232 450 60-61
260 500 59-60
288 550 57-58
316 600 55-57
343 650 54-55
*The above information is based upon personal experience and testing along with data from ASM International, Carpenter Steel and Crucible Service Centers.
790 is borderline too low. I do 820 with a 5 min soak once it is at temperature. Quench in warm oil an temper for an hour and a half at 200 Celsius.
That gives me splendid edges.
Thanks, Bruno! Than I will try to raise the temperature.
Thanks, Bruno. It looks like we will be getting O2 over here in the future without having to buy a huge sheet from Bestar in Georgia and waiting to have it shipped from Germany. The damascus makers are psyched.
WHo's going to make it or import it?Quote:
Originally Posted by JDM61
a certain Italian-American gentleman from New JerseyQuote:
Originally Posted by ScottGoodman
I will have to check with Aldo Bruno soon then...his shipping is so dang high any more that I have been ordering elsewhere.
From New Jersey Steel Baron:
We are gauging interest to see if it is worth bringing in. We have no set date or time for bringing it in as of now though.
I've seen these responses before, so I am not going to hold my breath on it.
Outside knife making circles, which is a really teeny tiny volume of steel customers, O1 is a better steel. For heavy duty use, the tungsten makes ir superior to O1. Only for knifemakers would O2 be better imo.Quote:
Originally Posted by ScottGoodman
Even TI can only get their steel by piggybacking their orders onto a buyer who buys 'real' quantities. Unless you're buying it by the tens of tons on a regular basis, it doesn't make sense to buy it. Especially since everyone who would like O2 is now using O1 or similar. So it's not like they're going to sell more steel by adding O2.
It would be nice, but probably not going to happen soon :)
All very logical Bruno, but I would point out that the one supplier who offered 02 would be taking a portion of sales away from all of the 01 suppliers, not just his/her own 01 sales.Quote:
Originally Posted by Bruno
Good point. It'll depend on volume then. Is the knife making community going to buy several metric tons on a regular basis or not?
It is my understanding that 02 is available in Europe, no? If so, isn't it just a matter of a U.S. vendor buying enough from a
European supplier to make the shipping reasonable? I've never looked into 02, so I may be completely out in left field.
I don't see it. I just received an order of 34# of L6 & 1095 from Admiral steel, enough to last me a LONG time...I would bet I don't order any of either for a year unless I need something thicker than what I have. I doubt there are many makers who go through more than 50# of steel in a year. I know there are more and more makers popping up, but most of those are scroungers...making stuff out of scrap like springs and such. I don't scrap hardly any, not worth my time as my time at the forge is precious to me and I'm not taking a chance on mystery steel. I have a few springs from railroad box cars and a new set of springs off one of our firetrucks that we replaced with aftermarket before we put the tanks on it, had them for a couple years and still in a pile...untouched.Quote:
Originally Posted by Bruno
Scott is right I think. If you see just how many people try to scrounge.... too cheap to even but a low cost known good steel, hammering pipe wrenches, railroad spikes or screwdrivers into a knife shape.
Shipping O2 is going to be horribly expensive. And you'd need to do it in large quantities. By the time it would arrive it would be twice as expensive as O1 just to break even. And then you'd need to find knifemakers to sell it to at pretty high prices compared to O1 which is already considered expensive.
I suppose you could do a group buy but the logistics would be very time consuming.
The guy that I was talking-to said that you can get the German steels from the manufacturers offices in the in the US, but you have to buy a good sized sheet of the stuff. The O2 and the "Hitachi blue substitute" steels are apparently sold primarily to the timber industry much like 15N20 is. That is probably why Bestar set up their office in Atlanta. The guys who clued me in to Bestar said that the shipping is not horrbile, but you might have to wait a few weeks because they will throw it in with one other big regular orders. He has bought some 1.2519 from them.
We just got a heads up on another forum that Voestalpine/B-U tool steel division office in the US has expressed a willingness to sell small quantities of some of their steel to us poor pitiful smiths. Not sure if the O2 is on that list, but I will try to find out. The Voestalpine /B-U strip steel guys have already done us a solid with the thicker AEB-L stock, so this may have possibilities. The Bestar guy in Atlanta said that the minimum order for O2 would be 1800 lbs and require a 6 month head start, so no joy there for us little guys.