liquid nitrogen quencing

N

not2blunt

Joined
Mar 28, 2000
Messages
9
Hi,
I AM CURRENTLY USING LIQUID NITROGEN FOR COOLING DOWN THE TEMPERATURE TO -40 FAHRENHEIT.I THEN TEMPER AT 350 FAHRENHEIT.
IT LEAVES ME WITH A ROCKWELL OF 60/61.
MY PROBLEM IS THAT WHEN I DO A STRENGHT TEST
THE STEEL EASILY BREAKS DURING BENDING.(TO HARD)
WHAT ARE THE RIGHT SEQUENCE FOR BEST RESULTS.ANY 12C27 EXPERTS OUT THERE?
 
If you are using liquid nitrogen, you are gettin a lot colder than -40. Probably closer to -300. As for the breakage, I would say that somewhere the blade got a little too hot in the heat treating cycle and probably was not tempered properly. 60-61 rockwell is pretty hard.

------------------
Danbo, soul brother of Rambo
 
Once you come out of your temper cycle(s), go to the the Nitrogen. The reason your blades are breaking is becasue of the increased change of austinite into martinsite. After you've Ni quenched the blade(s), go back for another temper cycle at 25F higher than your previous temper(s). This should eliminate your problems.

------------------
Ed Caffrey "The Montana Bladesmith"
ABS Mastersmith
www.caffreyknives.com
 
You must log in or register to reply here.
Back
Top