Heat treat with argon

[J.A.Jones]

I was thinking of drilling a 1/8" hole in my oven, and inserting a S.S. pipe into it. I would then hook it to an argon tank and turn the pressure down very low will my knife is heating.
Has eneyone tryed this? Will it work?

 

[Allen Blade]

Hello,

yeap i have.

First thing though you need to built a Retort
chamber,this can be a Square box built out of steel and assemble it with a welded bottom and a Screw attached lid,,,under the lid facing into the chamber weld little hooks to hold your blades suspended.

get some of the high temp Glass gasket sealer rope,small diameter and use this to seal the Lid when you tighten the bolts down to seal it.

Dril a hole in the top and put a two way valve in,this is where you fill the ARGON from.

Remember that ARGON is Heavier than AIR so you dont want to fill from the bottom. Fill from the top and as the chamber fill it will fill from the bottom up.

Also make sure you turn the ARGON bottle off good after use,or it will leak out and Float on the ground,although you cant see it.


Trial and error wel tell you how long to leave the gas on to fill your Chamber,as you cant see or smel it,the best way to tell if you have enough ARGON is to Fill it for like 5 minutes and then heat treat a batch.

if you had enough Argon in the Chamber your Blades will come out Scale Free and shiney if thats how you put them in ,in the first place. if not you need to let the gas run a few more minutes.

Turn the Gas off and tighten down the lid
and insert into furnace and start the heat treat cycle,,,this is only pratical for Air hardening Blade`s,,after the Cycle take out the RETORT chamber and cool in between two box fans to achive the hardening.

Again this will not work for Oil Quenched blades ,,,,,only Air hardening Blades!!

As you cannot get the lid off and grab and dunk a Carbon steel oil hardening blade fast enough before it goes Under Critical Temp.

Also just filling up your Furnace will not work as you can not seal the oven tight enough to keep the Argon from not leaking Out
which defeats the whole purpose and wastes ARGON which isnt Cheap by the bottle.

Hope this helps.

Take Care,
Allen Blade

[This message has been edited by Allen Blade (edited 01-13-2000).]

 

[Rex]

Please use this in a well ventilated area Argon is oderless and tasteless.Numerous people have been killed in the steel industry from Argon exposure. As stated it is heavy and will settle into low areas like cleanout pits etc.Workers going into these areas can't detect anything unusual and next thing you know they wake up dead!

 

[DCK8]

the best way to tell when you got an oxygen free atmosphere with out the use of an O2 meter is to wet your fingers and hold in front of the vent it will get cold from the argon i would fill from the low point and vent from a high point,you have to purge at a slow rate to keep from causing a turbulance ,ihave been a pipe welder for 13 years i weld a lot of exotic alloys that have to have a back purge and this is the way i have always done it another suggestion would be to use nitrogen i think you will find it a little cheaper than argon and just as effective