Please Critique my O1 Heat Treatment Procedure

Oh. Did you try to isolate which it might be, oil or stress relief? That thickness, just a shade over 1/4" if I'm right, should harden fine through. Did you change suppliers or did your supplier get a new heat of O1?

I am curious as to why choose O1? Is there surface hardness you need? Is the precision ground stock better for size/tolerance reasons? Did you already have a metric s... ton of it on hand? Surely there is something that would work just as good and be cheaper? Size availability? You can get O1 in just about any size you can dream up, from 1/64" to a couple inches or more, metric, imperial, rebel, :)
 
Do you bend them cold or in a forge? Did you change the radius of the bend? Did the ones that broke crack from inside out or outside in?
 
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Stress relief never hurts if done properly, especially if you cold bend them. Stress relief even helps corrosion resistance on stainless welds. Stress corrosion with or without cracking is a cast iron bitty.
 
me2 said:
Interesting. None of my sources show an Mf for O1. Buehler's data sheet shows up to 10% RA when quenched from 1470 F, while still getting a hardness of 65 HRc. A lot of this will be removed by tempering, but part of the quenches after tempering and the cold treatments are to get rid of as much as is possible without changing it to something other than martensite.
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MF depends on austentizing temp, and how much carbon goes back into solution. It can be as low as -100f to -200f depending on how heat treatment works. If you only get 0.8% carbon back into solution during austentizing, Mf is 100f to 200f.
 
Just saying what the people that make the steel found under a microscope. It's also becoming more apparent that there may not be an Mf, it's more like an M(as much as we can get).
 
me2 said:
Oh. Did you try to isolate which it might be, oil or stress relief? That thickness, just a shade over 1/4" if I'm right, should harden fine through. Did you change suppliers or did your supplier get a new heat of O1?

I am curious as to why choose O1? Is there surface hardness you need? Is the precision ground stock better for size/tolerance reasons? Did you already have a metric s... ton of it on hand? Surely there is something that would work just as good and be cheaper? Size availability? You can get O1 in just about any size you can dream up, from 1/64" to a couple inches or more, metric, imperial, rebel, :)
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PM sent.
 
I don't think I get PM's here. Try an email. I haven't seen any notifications yet if I do get PM's.

I just reread that question barrage. I didn't think I could to that any more. Sorry Fred.

On the Mf question, I have a couple charts for 1075 that show M95% near room temperature. O1 would only be lower due to the alloying and potentially greater carbon in austenite. Do you guys have new/better charts?
 
me2 said:
I don't think I get PM's here. Try an email. I haven't seen any notifications yet if I do get PM's.

I just reread that question barrage. I didn't think I could to that any more. Sorry Fred.

On the Mf question, I have a couple charts for 1075 that show M95% near room temperature. O1 would only be lower due to the alloying and potentially greater carbon in austenite. Do you guys have new/better charts?
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Its coming E-mail.
 
me2 said:
I don't think I get PM's here. Try an email. I haven't seen any notifications yet if I do get PM's.

I just reread that question barrage. I didn't think I could to that any more. Sorry Fred.

On the Mf question, I have a couple charts for 1075 that show M95% near room temperature. O1 would only be lower due to the alloying and potentially greater carbon in austenite. Do you guys have new/better charts?
Click to expand...

I was asking Kevin Cashen about this a few months ago. The way I understood what he was saying was setting up the steel by normalizing and thermal cycling got everything in solution, and evenly distributed. When austentizing, only get 0.8% carbon into solution to minimize retained austentite. This allows Mf to be at room temp or a bit above. If you get everything into solution when austentizing, the Mf will be below zero, and cryo will be needed to manage this.
 
I may be guilty of arguing for argument's sake. O1 should work fine w/o a cold treatment (not cryo, that is Liquid Nitrogen temps). I'm splitting hairs trying to get the very least amount of RA possible, maybe 3% or so. The issue of what is Mf and such is a different one and not specific to O1, which this thread is. A double temper should take care of the vast majority of RA, converting it to either bainite or martensite. I was just trying my best to ensure the latter.
 
We are here to learn aren't we? I love this forum, and the others. I wouldn't have an outlet to let you guys know how slow I am!!!!
 
Some people like to hit the spine of the blade with a torch between temper cycles and temper the spine back even more than the 400f oven temper (temper it to a blue color). Make sure to keep the bottom 1/3 (approx) of hardened blade in water and do not let the temper line move down into it.
 
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