heat treat HELP!!!!!!!!!!

[hardyferret]

Hi
need a few pointers please have made my 2 RM blanks and want to heat treat

I have got hold of an old electric kiln which heats up nicely to 800-820 c and accurate, am I best to suspend the blades vertically or lay flat or on their spines??
Which oil best for quench ?? As an apprentice did do some hardening but it's nearly 25yrs ago Which is better just dunk and leave or have a waggle??
How successful is tempering in the house oven, providing you don't get caught!!
Any other advice welcomed

Happy Chrimbo to you all

Hardyferret

 

[Ogri the trog]

Sounds like you have an ideal set-up there Hardyferret,
If the oven has a gauge you're laughing - though a little research on the actual temperatures you're aiming for will help. An overall heat up to non-magnetic (when it no longer attracts a magnet) is fine. I don't know about oreintation inside the oven, perhaps a little experimenting is needed.
Any oil will do for the quench though some people prefer certain types - cooking oil, engine oil, most will serve adequately for the job, if its a big enough vessel, a plunge should suffice but if its on the small side then a wiggle will help the process.
As for tempering, I always overshoot when doing mine, so I've learnt to be carefull and take things very slow - its easy to get the blade too hot and things start to turn blue rather than straw coloured.
Theres a mine of information over on Britishblades with tutorials and temperature charts if you have a search. My heat treatment gets done in the kitchen range and seems to be good enough for now.

What steel are you using? I'm guessing 01, so if its different, them wait for some other advice.

ATB

Ogri the trog

 

[forginhill]

double post, sorry

 

[forginhill]

If you're absolutely sure that your kiln is accurate then heat it up to non-mag like Ogri said. Most smiths go a few seconds past non-mag to make sure all the carbon is in solution. Not all quenching oils are created equal. Some are slower and some are faster. Mineral oil and automotive oils are slow. Canola oil is fast and acts very similar to the expensive quenching oils you can buy. You want the fastest quench medium you can get away with without cracking the blade. If you're doing a full quench then some up and down motion in the quench would be good. I tend to do edge quenches to leave the back a little softer/springier. I just stick it in and keep it still. Side to side movement in the quench is dangerous and leads to warping. I temper in a household oven but always use a thermometer in it to make sure the temp is accurate. You should also let it warm up for a half hour so the heat is even and stable. Hope this helps. Todd

 

[C_Claycomb]

If your kiln is really accurate, and you are using O-1, ignore the business about sticking magnets to things. O-1 needs a soak at temperature, at least 5 minutes, 10 is better if you have the control to keep the temperature constant. Heat to 810degC and hold it there for 10 minutes then quench. You might want to play with the precise temperature, just don't go fooling with magnets if the kiln is accurate already.

If you only heat O-1 just beyond non-magnetic and quench, you will not get full hardness.

Soak times will differ for other steels, but will apply to all the more complex alloys.

Inside the kiln just stand the blades on their spines, that will be fine, provided that the place you are standing them is not a cold spot

On tempering, a home oven will work fine. If you get full hardness via proper soak, everything I have seen or heard says that you will need to temper well beyond "Light Straw" colour. I saw some bits of 52100 steel that still tested at 60Rc but had been tempered into the blue range. You will have to experiment on tempering. My oven won't hold a constant temperature and if I leave the blade for much more than an hour at a time, the temperature can rise above where I want it. BUT, if you start off with harder steel, it is harder to overshoot so much.

For some good reading, look here:
http://www.swordforum.com/metallurgy/ites.html

http://www.bladeforums.com/forums/showthread.php?t=394824

http://forums.swordforum.com/showthread.php?postid=459210

http://www.knifebuy.com/forum/showthread.php?t=34126&

Best of luck

 

[hardyferret]

I'm impressed,

All this help and so quick, the kiln has a very nice themocouple feeding a analogue switching meter which Iam connecting to give me temp control in a band of approx +/- 5c which should be ok, tried kiln last night, 810c and the piece of 01 had the shimmery shadow. I know thats not very tech but we understand....
So over the w/end I will dunk my dirk.... and will report back
Once again many thanks

regards Hardyferret poss when I'm caught in the oven !!

 

[hardyferret]

Well the kiln did it's job and I got away with tempering in the oven!! Must be Christmas.
Now for the clean up and the scales hope to post pics soon, would love to keep the temper colour, but know it will wear etc

Thanks again for the help

Regards Hardyferret

 

[forginhill]

Glad you succeeded! Now you need to break a knife that you heat treated the same way so you can see if it really worked right. I just broke one last night and was pleased with the grain size. Helps me know I'm doing things right, making a dependable blade. Todd

 

[hardyferret]

BREAK IT!!!!

I've only just made it please don't say things like that
Not at Christmas.....

Regards Hardyferret

 

[forginhill]

A good writer once said, "Murder your darlings!" Gotta do it. (Wait till later in the year if you have to ) There's no other way to know for sure how effective your heat treating is. The grain should be invisible to the naked eye, just sort of a creamy look. If you're edge quenching for a differential harden, the grain in the upper, softer portion will be visibly larger. Todd