O1 vs 52100 Is the latter that much better?

D

Don Powell

Joined
Sep 21, 2001
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265
When one looks at the content of these two carbon steels,they
are not that much different. Yes, 52100 has three times the Cr
content, however does that make it that much better? According to
the information that I have read, 52100 borders on the Holy grail
of forging steel. It is hard to understand. Such a simple steel.
 
I know that I much prefer 52100. In fact, it is my favorite steel period. I think part of the reason 52100 is so popular and performs so well is that men like Ed Fowler have tweaked the heat treat to a point where they are getting the absolute most out of the steel. Mr. Fowler spends untold hours experimenting, and then puts his methods on paper for all to benefit from.

To my knowledge, no one has worked with O1 to the same degree. And the results probably would not be the same if they did. Looking at the composition of two steels and comparing them and making judgements based on that alone is a tricky business. A steel is more than just the sum total of its components. I'm not trying to imply that there is some kind of voodoo working, but we don'yt yet understand all there is to understand about the mysteries of carbide formation, the effects of minute differences in heat treat recipes, etc.

That is part of what makes this hobby so fascinating.
 
As Coonskinner points out, a steel is more than just the sum total of its components. One VERY important point is how and with how much care a steel is made. O-1 is a simple tool steel made by the steel industry for a lot of different, simple tool applications. It is melted down in the usual furnaces, poured in forms, hot rolled and that's it.
52100 is a steel developped to make roller bearings from. Here we have an application requiring a steel that is perfectly homogenous and fine grained. For this reason 52100 is made with a lot of care, usually using vacuum or protective gas melting methods. That's the reason why it costs a bit more as a raw steel, too.

To show you that it can be even closer than what you mentioned, i will show you an example from over here in Germany. There are two different steels you can buy from the steel suppliers. The DIN name of BOTH steels is 100Cr6. The alloy content is ABSOLUTELY the same. The Werkstoffnummer for one is 1.2067, for the other is 1.3505. The first is declared as a cold work tool steel. The second is declared as roller bearing steel. It is 52100. The properties are definitely NOT the same.

Achim
 
The best basis of comparison I personally have is from MasterSmith Wally Hayes. I have both 52100 and O1 blades of his. The 52100 is extraordinary, but the O1 is quite good too. It is a subjective impression but I get the feeling that the 52100 is more flexible and resilient. Anyway, I wonder what Smiths and makers who use both have to say? I think there is a significant price difference as well.
 
Don, that small amount of Chromium in 52100 makes a Big difference. Cr is a strong carbide promoter. It changes the crystal stucture of the steel significantly at very high temperatures.

When properly heat-treated, the structure of 52100 is homogeneous and very fine grained. Steel does not need to be highly alloyed to make a great knife. O1 is a fantastic knife steel. The small amount of Cr in 52100 obviously does not effect stain resistance at all, but it can have a significant effect on the working properties of finished blade steel. It also makes 52100 much more difficult to forge and heat-treat properly compared to O1.

For the same reasons that Cr can improve the working properties of a steel, it can also adversely effect it. The large amounts of Cr in 'stain'resistant' steels make them difficult or impossible to forge, and promotes the growth of very large crystal structures which may make a blade difficult to resharpen, hard to get really sharp, and may hasten edge wear by chipping.

"The dose makes the poison" a quote from the Real Paracelsus :)
 
Thanks guys for your input. I do indeed understand that 52100
probably has many more of the hard Cr carbides, However O1 Has
Tungsten and these carbides are very hard also. The point
about the purity of the alloy is a good one.
It is my understanding that the fine grain structure is a
function of the heat treat process, and I can't help but think
that the multiple normalize, multiple quench, ect. would also
make O1 a great knife steel. I just bought a piece of O1 and
although I cannot forge it, I plan to find out what triple
everything will so for it.
Don Powell
 
There is a lot more to 52100 than just the chemistry. The amount of forging prior to heat treat is extremely important to the end results.
Ed Fowler has done many experiments with different size ball bearings as his starting material and has shown that the more mechanocal reduction put into the material, the better the finished blade.
I know of at least 5 different chemistries that are types of 52100. They are very different. Some are designed for deep hardening and some are tweaked to allow better machinability.
I don;t know of a soure of o-1 that is of a size that 52100 can be purchased in. This limits its reduction .
Multiple heat treat procedures will probably help refine the grain size of most steels.
Take care
Rex
 
52100 has the nick name 'Cadillac of steels' in the roller industry. Bearings made today are better than ever, this is due to commitment in the steel industry and standards that have been developed by the ASTM and the industry. The 52100 steel that I have been using is far superior to the ball bearings I used to use simply because they came from many times and places. Some were great, some yielded blades that failed my tests. I learned a lot using the old ball bearings, now that I am using the 52100 from Rex, I am enjoying a steel that is absolutely reliable, consistent and a joy to make knives from. The steel is forged down at low temp from 5 1/2 to 6" round stock. This amount of reduction by forging to a knife blade provides a supreme opportunity to push the steel to the limit. The experiments continue and the learning opportunities are an absolute joy. Obviously my vote is for 52100.
 
But, for the average stock removal guy who cannot forge his blades, even Ed might agree that O1 would be the better choice. O1 being much easier to heat treat properly than 52100.
 
It all depends, to you want an easy blade to heat treat or do you want to make the Excalibur of the future? Challenge provides opportunities. If I learned, anyone can lern.
Take Care
 
Ed Fowler, wow! I am humbled. Ed, my copy of Knife Talk is
really starting to show some wear and I really have read your
words. I think that we may be talking apples and oranges here.
Since I do not have the means to forge, my thoughts were of
stock removal. If one looks at the data from Crucible, for
example, the results of wear resistance and toughtness are quite simular between O1 and 52100. Even Wayne Goddard has made
a comment that indicated that he wanted to test them side by
side, thinking they might be equal.
I have no idea how much the forging process adds to steel. I
have always had much affection and respect for the forged blade
and the Bladesmiths that forge them.
Don Powell
 
Iv'e been using 0-1 for 14 years now and it performs great. I also think 52100 is awesome. I like them both a lot.
If I could get precision gorund 52100 for the same price as 0-1 I would use more of it. But some of my knives would double in price if i had to forge to shape the 52100 and all the extra work involved in finishing 52100.
Cheers, Wally
 
Howdy,
I've got a question about the diameters to use in hand forging 52100, Mr. fowler uses biggggg stuff which is out of the question for me sense I don't have a power hammer, but will I lose that much superiority if I forge blades out of smaller stock,like 1/2" round or 3/4" square. I forge mostly 5160, and really love the blades it will produce, but with it I'm talking 1/4"x1 1/4' flat stock, and which would be the best size to forge out of, round or square or does that really matter.
Comparing it to 5160, it appears to forge and heat treat pretty much the same with just longer peroids between quenching sessions,
and Mr. Fowler recommends freezing, there again with out the freezing process, will it produce a quality and excellent blade. I know that he's (Mr,Fowler) producing the best blades the steel has to offer, but I'm not set up for the freezeing part to extreme temps, but would it be beneifial to put in a freeze for a day or 2 and then temper one last time, or would the extremes not be enough to be beneifial.

Thanks
Bill
 
Thanks for the kind thoughts, I like to hear that Knife Talk gets read and my knives get used. I strongly feel that the more mechanical reduction (forging)you can do to your steel the greater the performance potential, providing you do nothing to hurt the steel. Low temp forging in the vicinity of 1625 f will cause no measurable carbon loss and will not cause grain growth. I freeze my 52100 blades in my home freezer, right next to the ice cubes, between quenches. If your forging and heat treat is where it should be liquid nitrogen freeze is not necessairy, it will help make up for a heat treat that is a little off center. If you are limited to stock removal, low temp thermal cycles, barely above and below critical, can improve performance. I love my power hammers, and would hate to have to make knives without them, but there are hydraulic presses and treddle hammers that will help. Most important is get quality steel, work with the same lot and you will know good times. It is fun to make knives out of scrap, and cheap way to hone your skills but it can be misleading as you wil tend to blame your technique when the fault may lay in the steel. It took me a long time to realize not all steel is honest. If I had to choose between 01 and 5160, I would choose 5160. It is forgiving and makes a good knife. My first experience with 01 was not pleasant, but I have learned a lot since then and might be able to work it out. Quality of the O1 would be my prime concern as it has not, to my knowledge been subject to the research that 52100 has surrounding it.
Take Care
 
It is my opinion that when it is done by Ed, there is not a better steel than 52100, period. Others may make better knives with other steels because they have worked with them more and know how to get the best out of them, but Ed has put many years into improving the forging, tempering and heat treating techniques used to make 52100 a great knife steel. There are other steels I really like, but none as much as 52100 when everything is done right.

O1 is a very good steel and is used to make some great knives, but to me many other carbon steels are as good and maybe better. This is something I can not say about 52100. I don't think that the perfect knife steel has come along yet, but until it does 52100 will do just fine for me.
 
I would like to sincerely thank all those people that have
responded to this post with their thoughts and opinions. I
would like to make a correction to my last post. I meant to
say, I have no idea how much forging improves O1. I think
Ed Fowler has more than convince me how much forging improves
52100. Ed, thanks so much for your input. After reviewing all
of the above, I think it is safe to say that O1 is a lesser
blade steel than 52100, how much I still don't know. Maybe
some more people that has worked with O1, can give us their
thoughts.
Don
 
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