- Joined
- Sep 9, 2003
- Messages
- 2,361
It could still be O-1 and there could be any number of variables interfering with the outcome you desire. the biggest problem is that we are trying to troubleshoot a problem over the internet. I once showed a student how to draw a spine with a torch, and then walked away to help some others only to have him come back a while later complaining that the edge was too soft. Upon examination that edge was the prettiest blue color with the spine fading from straw to bright silver- yes after a good heat treatment he had put the spine in water and ran the torch along the edge of the blade! This is just one of hundreds of stories that I could share that happened with me being physically present in the same room as the person attempting the procedure- now how likely do you think it is that these things will come off without a hitch simply describing touchy temperature operations over the internet?
If your steel has heavy carbide segregation from improper prior treatments any number of anneals will still make real soft steel with big drill dulling clusters of carbides. This is why normalizing in the 1600F-1700F range is recommended by industry, it will dissolve those carbides and scatter them. If things are really being a pain the next heat could be from 1475F -1500F and then quenched to lock carbon in solution and keep it from separating on cooling. From the fully hardened state the next heat is to take the carbon out of solution the way you want it not the way it wants to. That heat must stay below non magnetic, if you go above the Currie point you will have exceeded your desired range by around 50F. and the carbon will go into austenite that will simply make upper bainite or perhaps even martensite as soon as it cools and you will be right back to square one. If this happens the carbon will also have the opportunity to gather back up and challenge your drill bits.
Keeping it below the Currie point will do one of two things depending on the temperature you go to. From 1375F to 1325F will pull carbon marginally into solution and engage what is called the divorced eutectoid reaction that I will not go into as it is rather technical in ways that would not help clarify matters here. The cycling in this range will move the carbon in a very limited way which will encourage it to separate out into spheroidal groups that do not engage the surrounding iron. Most smiths will choose to keep things cooler and simple by just heating to a range from 1200F to 1300F which is basically a very extreme tempering operation that produces spheroidal cementite instead of tempering carbides.
In summary - In either of these operations if you go hotter than the Currie point at any time you will have defeated your purpose. With out standing over your shoulder I can only say that if you do not break up those carbide sheets with a good hot normalizing, it will squeak your drill bit (1095 is miserable for this, and I have even done it with 1084 if not careful). Once the carbon is dispersed it must not be allowed to cluster back up by slow cooling from above critical - this is why vermiculite, wood ash or kitty litter can be one of the worst things to do. Fast cooling such as air or even quenching, if done from a quenching temperature cycle, will avoid this issue and keep the carbon where you want it. To then ball it up and make it easy for the drill bit to move, you keep things below non-magnetic. It is subtle and takes a little experience or skill but it does work every time once you get the hang of it, but short of that is exactly one of the reasons why I do not recommend hypereutectoids with alloying like O-1 for folks just starting out despite the prevalent yet completely false idea that it is a good beginner steel.
If your steel has heavy carbide segregation from improper prior treatments any number of anneals will still make real soft steel with big drill dulling clusters of carbides. This is why normalizing in the 1600F-1700F range is recommended by industry, it will dissolve those carbides and scatter them. If things are really being a pain the next heat could be from 1475F -1500F and then quenched to lock carbon in solution and keep it from separating on cooling. From the fully hardened state the next heat is to take the carbon out of solution the way you want it not the way it wants to. That heat must stay below non magnetic, if you go above the Currie point you will have exceeded your desired range by around 50F. and the carbon will go into austenite that will simply make upper bainite or perhaps even martensite as soon as it cools and you will be right back to square one. If this happens the carbon will also have the opportunity to gather back up and challenge your drill bits.
Keeping it below the Currie point will do one of two things depending on the temperature you go to. From 1375F to 1325F will pull carbon marginally into solution and engage what is called the divorced eutectoid reaction that I will not go into as it is rather technical in ways that would not help clarify matters here. The cycling in this range will move the carbon in a very limited way which will encourage it to separate out into spheroidal groups that do not engage the surrounding iron. Most smiths will choose to keep things cooler and simple by just heating to a range from 1200F to 1300F which is basically a very extreme tempering operation that produces spheroidal cementite instead of tempering carbides.
In summary - In either of these operations if you go hotter than the Currie point at any time you will have defeated your purpose. With out standing over your shoulder I can only say that if you do not break up those carbide sheets with a good hot normalizing, it will squeak your drill bit (1095 is miserable for this, and I have even done it with 1084 if not careful). Once the carbon is dispersed it must not be allowed to cluster back up by slow cooling from above critical - this is why vermiculite, wood ash or kitty litter can be one of the worst things to do. Fast cooling such as air or even quenching, if done from a quenching temperature cycle, will avoid this issue and keep the carbon where you want it. To then ball it up and make it easy for the drill bit to move, you keep things below non-magnetic. It is subtle and takes a little experience or skill but it does work every time once you get the hang of it, but short of that is exactly one of the reasons why I do not recommend hypereutectoids with alloying like O-1 for folks just starting out despite the prevalent yet completely false idea that it is a good beginner steel.
I honestly never knew O1 was this complicated but, I am learning! 
) and I'm trying to get stuff together for a show this weekend. The steel will probably go monday or tuesday