Info about O2 steel

There has been a lot of discussion about the relative merits of cryo for O1. If you Google around, you'll see discussions at hypefreeblades forum, knifedogs, here, knife network.

Much of it has to do with the martensite finish (mf) temp of O1. Also, mf temps will vary depending on how much of the carbides were in solution at the time of quenching (i.e., austenitizing times and temps.)

There are some rather wild claims, depending on where you look, concerning the results of cryo for given steels. Also technical literature can be frustratingly varied form source to source.

I will say, that O2 sounds pretty attractive...
 
i have read the jayfisher piece also, you go into the fine print and you see he is talking about a 24-36 hour treatment with precise cooling and heating ramps, not something most of us have access to. did you get any paperwork with the steel? how big is the rough nakiri?
scott
 
the steel is Starrett O2, PG and spheroid annealed. the composition is written on the paper it came in

C .90
Mn 1.20
Cr .50
W .50
V .20

The blade itself is about 8.5 by 2.5, the bevels are ground and ready for HT
 
Yeah, the Euro stiff has more manganese. i have seen some quoted as having 2%.
Greenberg Woods said:
the steel is Starrett O2, PG and spheroid annealed. the composition is written on the paper it came in

C .90
Mn 1.20
Cr .50
W .50
V .20

The blade itself is about 8.5 by 2.5, the bevels are ground and ready for HT
Click to expand...
 
PEU said:
With my oven I use 805-810C (1481-1490F) and quench in preheated oil, if the blade is long, like in a yanagiba or long fillet knife, when it still hot and fuming I put it inside my stainless setup (2 alu 1" thick long sheets) with a heavy piece on top. It comes out straight as an arrow and hardened as expected.


Pablo
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What Pablo said. O2 and 01 are some of my favorite steels for monosteel and damascus. The onlu dteel I like more is 115w8 wich is not available on the states.
A bunch of O2 is a great score.
 
Greenberg Woods said:
the steel is Starrett O2, PG and spheroid annealed. the composition is written on the paper it came in

C .90
Mn 1.20
Cr .50
W .50
V .20

The blade itself is about 8.5 by 2.5, the bevels are ground and ready for HT
Click to expand...

what you have is Starrett's O1. I have a bunch in the shop, goood stuff.
scott
 
Salem Straub said:
There has been a lot of discussion about the relative merits of cryo for O1. If you Google around, you'll see discussions at hypefreeblades forum, knifedogs, here, knife network.

Much of it has to do with the martensite finish (mf) temp of O1. Also, mf temps will vary depending on how much of the carbides were in solution at the time of quenching (i.e., austenitizing times and temps.)

There are some rather wild claims, depending on where you look, concerning the results of cryo for given steels. Also technical literature can be frustratingly varied form source to source.

I will say, that O2 sounds pretty attractive...
Click to expand...

Cryo will help you with retained austentite. In industry higher temps for larger carbides are used, for better wear resistance.cryo helps in that application. For knifemaker's, lower austentizing temps around 1475 prevent retained austentite, so cryo is not needed.
 
IDK. That was the wrapper on some sheets of .25 thick, on the sheets of 1/8 the steel has O2 printed on it, those did not come in paper. So im not sure
 
So you may have both. I looked up the specs for old Starrrett O2 and it has like .3 moly and .3 nickel in lieu of tungsten and 1.4-1.8% manganese. the good news is if the 1.8 is O2, you have some nice stock for damascus.
Greenberg Woods said:
IDK. That was the wrapper on some sheets of .25 thick, on the sheets of 1/8 the steel has O2 printed on it, those did not come in paper. So im not sure
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jdm61 said:
Does Starrett's version of O1 have no moly?
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the Starrett O1 i have has the 'Standard' American blend. 0.95 C 1.25 Mn 0.5 Cr 0.5 W 0.20 V 0.35 Si the same formula used in Carpenter's O1. Most of the O1 I have is NOS, probably let over when machine shops started going to A2 as a GP steel because it is easier to heat treat than O1. Talking with local machine shops, the biggest part was not having to maintain a quench oil system and the associated hazmat.
the only O1 i have seen with moly is that marketed by Niagara Spec. Metals(http://www.nsm-ny.com/index.cfm?fuseaction=page.display&page_id=30), but they do not sell it in their online store and none of their suppliers seem to have it.
scott
 
Greenberg Woods said:
Hey, just wanted to update this. Just ground a 2.5 inch tall Nakiri out of this, and it works like a dream. The stuff is PG and soft as butter.
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Not trying to derail this too much but is this the nakiri that you mentioned in this other thread?:

http://www.bladeforums.com/forums/showthread.php/1413804-Hello-Socal-knifemakers!

where you stated:
Greenberg Woods said:
I only have pretty terrible photos of my knives, But I will be doing a WIP as I grind out a new large Nakiri
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I was looking forward to that WIP. :(
 
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