0-1 RC hardness question

blgoode

blgoode

Knifemaker / Craftsman / Service Provider
Joined
Oct 3, 2003
Messages
7,145
I will be using 0-1 for some time to come...I like it so far ;)

Anyway, does anyone know the RC for the different temper temps?

375 degrees=RC?
400 degrees=RC?
425 degrees=RC?
450 degrees=RC?

This may be one for RLINGER.......

I will need to know these harness estimates for better quality control....

Thanks in advance.
 
First I would scap the primary tempering temperature(s) below 400 F. Begin at 400 F as your low end. I truely do not know by experience and would have to refer to the data sheet for advise on that. Another consideration is whether or not a deep freeze is used. I would guess that you could expect a neighborhood of 59 HRc if tempered one hour at 400 F and then tempered 375 F for one hour and without a deep freeze. I just haven't done that much blade work with O1 to be of any real help on that.

RL
 
thanks RL. I talked to a knifemaker today who say's he tempers at 450 for 0-1 and 1095/L6.

Seemed high to me but this guy has been a full time maker since 1988 so he knows what he is doing ...

His name is Daniel Winkler. I was lucky enough to get to stop by his shop today......VEry cool and a gentle guy. I tend to get spastic in the shop.....he was way more relaxed :D
 
Can't figure out where this printout is from, but here's one for AISI O1:

"Temper twice with intermediate cooling to room temperature. Lowest tempering temperature 360F. Holding time at temperature minimum 2 hours.

400F 60-62
450F 59-61
500F 58-60
550F 56.5-58.5

Approximate numbers from graph. First is with austentizing temp of 1455F, second is at 1510F



Crucibles chart:
As Quenched 63-65
300 63-65
350 62-64
400 61-63
450 60-62
500 58-60

Cintool.com's chart

1475-1550F quenching temperature gives the maximum hardness of 65
Tempering:

As quenched 65
300 63
350 62.5
400 62
450 61
500 60


Paxton & Vierling Steel Chart:
200 63/65
300 63/65
400 60/63
500 58/60


I'm rather fond of O1, if that wasn't already obvious. :)
 
Also, if you serach through this forum(or maybe archives, if there are any) there's a rather long thread titled "Thermal Cycles to refine Grain Structure(O1, 1084, 1095)" that I started last march that got a lot of good input on HT O1 from various experienced makers here.
 
BL, I would suggest your tutor should be listened to. I did not notice a deep freeze mentioned so I assume none. 450 F may not be too high. Do not approuch 500 or above though and if tempering at 450 F be sure to use a good thermometer to assure you will not achieve 500 F or above.

Interesting list of HRc provided above. I haven't even looked at O1 data for well over a year and a half.

O1 enjoys an interrupted quench. I believe pulling from quenchant at about 350 F and allowing to still air cool to about but not lower than 125 F before putting in preheated temper works real well for O1.

RL
 
Yes those figures are reasonable. The 450F max is a good idea because some undesirable things happen at 500-600F. ..It is a good idea to check oven temperatures once in a while !! I just did with my kitchen oven since I needed 175F .I put in a thermometer and found it was 300F !! The thermocouple had just gone south !A project for tomorrow.
 
Yeah, my kitchen oven runs approximately 100+ F high. My lady's has always since new run about 50+ high. Then we have the fondly used toater ovens for our tempering needs. They are not much better in temperature precision.

BL, after tempering your O1, or any non-stainless tool steel, you should notice the blade is goldish in color or the straw color knife makers usually love to see. If after tempering you see blues and/or purples you have gone way too high.

RL
 
Thanks guys.....I acheived that nice straw color at 425 the last time I tempered 0-1....you guys are the best...
 
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