52100

S

swingline327

Joined
Nov 6, 2013
Messages
17
I have circled round and round researching the "best" procedure to heat treat 52100.

I am going to outline my plan and ask the 52100 gurus for help.

Normalize: 1650 5 min cool
1550 5 min cool
1450 5 min cool
x3
Austentize: 1475 15 min soak
quench in 130 deg. canola to handleable
x3
Temper: 400 deg for 2hrs
x3
 
Good starting point. A couple of things you need to be sure:
1- be sure of your temperatures
2- start your timing only after the piece reach the set temperature... maybe for the first 1650 °F soak 8-10 minutes is more effective.
 
I'll be using an enameling kiln with a pyrometer, so the temps should be close. Thanks for the tips stezann.
 
I usually do something along the lines of this, including a subcritical cycle......One quench only after cycling, not three.

1650 20 minutes, air cool to black
1550 10 minutes, air cool to black
1450 10 minutes, air cool to black
1375 10 minutes, air cool to black
1475 10 minutes, quench 130°F canola
400°F one hour, at least twice. 375°F for kitchen knives, 425°F harder use knives, water quenching between tempers always

You can always do variations, as in...
1650 , then 1475 two or three times, then 1375, then harden.
 
I would recommend Stuart's regime.

Parks AAA or a medium speed commercial quench oil would be a slightly better quenchant than canola, but canola should work just fine.
 
Also remember that there will be a LOT of scale build up from the high temps and long soaks so you might want to wrap it in ss foil to protect it during the normalizing steps and then remove the foil before quench.
 
I use salt pots so I don't get a lot of scale. Most of the scale I get is after the salt runs down the blade when it's still air cooling.

1650 for 10 mins. air cool
1550 for 10 mins. air cool
1500 for 10 mins. air cool
1475 for 10 mins. air cool
1550 for 10 mins. quench in 400 degree salt, let it soak for about 6 or 7 minutes, then air cool. Replace in low temp salt for one hour and I get a consistent hardness of 60. What little scale I get is easily removed. If I'm doing a large batch I'll soak the blades overnight in vinegar and have scale free blades the next day. I just start the soaking as I'm leaving for the day.

**Note** On my setup, testing showed I wasn't get full hardness on anything less than 1550 degrees before quenching. Just one of the differences in quenching with salt instead of oil.

The next batch will be followed by a cryo quench to -300 after tempering. I found a place not to far away that charges 50 bucks a quench with as many blades as I can fit into their chest freezer setup. I should be able to do an entire batch at once for only 50 bucks. 70 knives for 50 bucks is hard to beat.
 
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