Hardening 1095 to very hard

I

itrade

Joined
Jul 3, 2002
Messages
645
I'm made some filing jigs out of 1095, 1/4" thick about 2x2". Last night I hardened them, well tried to. One side came out fine the other didn't. Obviously for a filing jig I need the hardness up over 64. Here's the details:

----------------------------
Propane weed-burner forge

Heated to glowing red, test for non-magnetic, back in the forge for 20-30 sec in the forge, then straight to the water.

Quenched in 1/2" corn oil over water, water temp varied from 120 to 180+ (I wasn't paying attention).

I had to do each one twice.

One is harder than a file, the other isn't really hard at all.
-----------------------------------------

Question:

What should I try to fix? Keep the water temp down, heat longer, heat hotter, use salt water, ??

Steve
 
There are two likly problems that you may be running into.

1. Steel not hot enough before it is quenched. The curie point (magnetic transformation) in hypereutectoid steels is your minimum temperature to quench from.

To test heat the part a bit hotter and requench.

2. Steel decarb; at high temperature steel in an oxidizing enviroment looses surface carbon rapidly.

To test grind or file the part down about 1/16" or so and retest with file. Soft surface and hard core indicate decarb problems.


Quench Medium:

Light room temperature oil (cooking oil, 10wt motor oil, atf etc.) is the recommended quenching medium. Water or brine will get you an extra point or two of hardness and increase the chance of quench cracking.
 
nhamilto40,

So if I understand this right, if I've decarbed the surface, I've ruined my jigs? Ouch. Just how fast is fast on decarbing?

I'll try your file test. Then, I'll try a brine quench and hope for the best.

Thanks much for the information.

Steve
 
It is hard to say how fast your steel will loose carbon without exact measurments of the your time at temperature, the weed burner's combustion products etc.

So just do it experimentally. Requench your part from a higher temperature and check surface hardness. If that resolves your problem it was probably not decarb. If not then test for decarb (and most likly ruin you part in the process).
 
try a pure water quench with the water temp down about 60-70 deg f, at 1/4 thickness you probably wont have to worry about cracking, and warpage shouldn't be a problem with a 2x2 piece. i have tried quenching 1/4" 1095 in water from 45 deg f to 150 deg f and never had cracks, i did have some warpage but i was quenching 1/4 x 1 1/4 bar stock in 2 ft lenghts
 
FWIW,

Thanks guys. It was just not quenched fast enough. I used 60 degree water and worked fine. No decarb problem (thank goodness). Jigs all ready.

BTW having curved jigs is nice for bolster/slab fitting. Not zero amount of fitting work, but not much.

If anyone is interested I can post a pic.

Steve
 
You must log in or register to reply here.
Back
Top