1084 Blade Failure

[panch0]

I really liked how his little hunter was coming out. I tempered it last night, cleaned it up today and put the forced patina on it. I noticed it had a little warpage. I got this steel a while back from Admiral. The stick came bowed. I bent it straight before grinding and checked it before heat treat. I looked at it after ht and it looked straight. When I lay the knife against the handle material I could see that it was warped a tiny bit. I use the three point bending trick and I heard the snap. After crying I figured I would break the blade portion and look at the grain. I put the tip in the vise and swung, it snapped and flew across the garage.


Here is the heat treat I did.
ramp up to 1500 and stabilized for 20 minutes
inserted blades in the oven and soaked at 1500 for 10 minutes
quenched in 125 degree mcmaster carr 11 second oil
tempered twice at 400 for two hours each

It tested at RC60 with my Ames portable hardness tester
A 60 rc file barely scratched it

Here are the pics of the grain.

 

[Russ Andrews]

It's nearly impossible to tell much about grain from those pics...too small.

60Rc is too hard for straightening. At that hardness it may flex slightly...then

do just what yours did.

Next time, try pulling the blade out of the oil 1-2 seconds after it's no longer

red. It will still be too hot to touch bare handed, but soft enough to be straightened.

 

[Jason Fry]

dang, hate it when that happens.

grain looks good, best you can tell from the pics

try rick's clamp and temper trick next time

 

[sunshadow]

You definitely should not have tried to straighten it cold after heat treat

-Page