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Oil for temper steel

Hi everyone, I use to temper steel in milling,cutting oil or 10w30
oil. I know that there is steel made to be tempered in water and
other in oil (the one I buy) but is there a special oil especially
made to temper steel, or there is an oil for each different steel.
Can you tell me about different oils used for differents steel.

Guy Audette
Quebec city

Hi Folks… Takes me back to another era…

Years ago when studying martial art I made up some "ninja spikes"
out of 1/4 O-1 (oil hardening) drill rod…

Automatic transmission fluid (with all of the warnings about
ventilation, etc.) is what I used to quench…there are special
quenching oils (i.e Tough Quench)… that wet out the stuff with more
speed, reducing the tendency for gas or heat pockets to keep the
hardness consitent…but tranny fluid seems to work pretty

To temper is the next part of the process…as quenched O-1 should
be at about 63 to 65 Rockwell (RC)…otherwise known as extra file
hard…it is also somewhat brittle, limiting it’s toughness…

To temper…you do what is known as a draw heat after quench for
about an hour or so…for example…at about 500 degrees F…you have
knife hard, which should be kind of a dark straw yellow…if you draw
at 700 degrees F, you wind up with a spring (dark blue to blue-gray)

Same kind of thing for W-1 (water hardening), but I’ve seen refs for
using a brine solution to quench…different draw temperatures, as
the starting quenched hardness is higher…

I have used a rummage sale toasteroven to draw heat small

Gary W. Bourbonais

Hi Guy; I should know this, but as for my blacksmithing, I am an
"old-tech" blacksmith and tend to work with anachronistic methods and
materials. You should run that question by the folks on the
alt.crafts.blacksmithing newsgroup. I’d wager there are some
individuals with enough metalurgical knowledge to not only give you
an answer but provide you with a few sources.

David L. Huffman
David L. Huffman Studios, Inc.

Steel used to be tempered in whale oil but, of course, that isn’t
possible now. You should avoid using motor oil as that contains
additives which may affect the state of the steel - sulphur,
surfactants, antifoam, etc. Any plain mineral oil will work well as
will most vegetable (cooking) oils.

Best wishes,
Ian W. Wright
Sheffield, UK