Heat Treatment Of Milling Cutters Drills Reamers Etc
:
HIGH-SPEED STEEL
:
The Working Of Steel
THE FIRE.--Gas and electric furnaces designed for high heats are
now made for treating high-speed steels. We recommend them for
treating all kinds of Blue Chip tools and particularly the above
class. After tools reach a yellow heat in the forge fire they must
not be allowed to touch the fuel or come in contact with the blast
or surrounding air.
HEATING.--Tools of this kind should be heated to a mellow whi
e
heat, or as hot as possible without injuring the cutting edges
(2,000 to 2,200 deg.F.). For most work the higher the heat the better
the tool. Where furnaces are used, we recommend preheating the
tools to a red heat in one furnace before putting them in a white
hot furnace.
COOLING.--We recommend quenching all of the above tools in oil
when taken from the fire. We have found fish oil, cottonseed oil,
Houghton's No. 2 soluble oil and linseed oil satisfactory. The
high heat is the important thing in hardening Blue Chip tools.
If a white hot tool is allowed to cool in the open air it will be
hard, but the air scales the tool.
DRAWING THE TEMPER.--Tools of this class should be drawn considerably
more than water-hardening steel for the same purpose.