Test analysis input wanted!

[Guy Thomas]

This evening I put the finishing touches on the hunter/utility knife blade I'm making to get it ready for heat treat.

After reading any number of posts here, I had begun to doubt my ability to heat treat this at home or that the large saw blade I got the steel from was actually L6 or something similar, so I decided to test a small piece I had filed into the shape of a blade some time ago.

With two jumbo flame hand held propane torches and a fire brick enclosure I rapidly got the steel up to a yellow orange and when tested with the magnet on the end of my scriber, it didn't stick! I heated for a moment longer then quenched in room temp. oil. A file test seemed to produce a "glassy" feel but also some small scratches but no real "bite".

I then took the blade put it in my vise, got some vise grips and (with considerable effort!) broke the steel (a nice clean break)to observe the grain.(And yes I did have eye protection on!)

It seems to be somewhere between smooth and velvety and coarse and grainy, (closer to smooth than coarse) so I suspect I actually got the steel a little too hot but considering that I had to put a good bit of my weight (210 lbs.) into breaking it I think it would have been fine after tempering. The surface of the steel also showed small pitting, would this also be an indication of over heating the blade?

My conclusion is that the steel is L6 or something similar and that I can heat treat this blade with a little luck and get good results, what do you think?-Guy Thomas

[This message has been edited by Silent (edited 07-01-2000).]

 

[tejas7]

It sounds like you are doing everything right so far. If you have the equipment to get a carbon steel blade hot enough to be non-magnetic there is no reason not to do the heat treating yourself.

You may have to experiment a little, but you will be able to obtain excellent results with out the expense and worse the waiting time needed when you send your blades away.

On almost all of my blades, I like to draw back the spine to a nice spring temper for extra good overall performance.

 

[Jonesy]

Sounds like you are on the way to me.

One thing I do is keep a log book of the events as I heat treat so if I need to I can change one variable at a time, kiln temp, oil temp,soak rate time. It is probably over kill but I like to tweak the process for better or worse. It is the only way I know to improve it and maintain some consistancy.
now take this and 50cents and get a cup of coffee.
Jonesy

------------------
Scott Jones
Heck yea I invented it ...What is it???
I only do what the voices in my wifes head tell me to do.
It's kinda like hangin, you never get used to it.

 

[mikeS]

Was this an edge quench? What was the condition of the steel before you quenched it, normalized, annealed, or previous condition from the sawblade?

 

[Guy Thomas]

This was a piece of one of the teeth of the saw blade that I had previously annealed by heating to orange-red and cooling in a coffee can filled with vermiculite. It filed very easily and I profiled a 2 1/2" folder blade from it (flat bevel of course).
I heated the entire blade and quenched edge first in around 90 degree vegetable oil. (I have built an immersion heater for the oil tank but did not want to wait half an hour to let the oil get up to around 130 degrees or so.)-Guy Thomas