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Hardening Carbon Steel For Tools
For years the toolmaker had full sway in regard to make of st...

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

Carbon Steels For Different Tools
All users of tool steels should carefully study the different...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

Heat-treating Equipment And Methods For Mass Production
The heat-treating department of the Brown-Lipe-Chapin Company...

Critical Points
One of the most important means of investigating the properti...

Air-hardening Steels
These steels are recommended for boring, turning and planing...

Crankshaft
The crankshaft was the most highly stressed part of the entir...

Piston Pin
The piston pin on an aviation engine must possess maximum res...

Furnace Data
In order to give definite information concerning furnaces, fu...

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

Manganese
MANGANESE is a metal much like iron. Its chemical symbol is M...

The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely nece...

Flange Shields For Furnaces
Such portable flame shields as the one illustrated in Fig. 1...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

The Thermo-couple
With the application of the thermo-couple, the measurement of...

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...



Hardening High-speed Steels






Category: HIGH-SPEED STEEL

We will now take up the matter of hardening high-speed steels. The
most ordinary tools used are for lathes and planers. The forging
should be done at carbon-steel heat. Rough-grind while still hot
and preheat to about carbon-steel hardening heat, then heat quickly
in high-speed furnace to white heat, and quench in oil. If a very
hard substance is to be cut, the point of tool may be quenched in
kerosene or water and when nearly black, finish cooling in oil.
Tempering must be done to suit the material to be cut. For cutting
cast iron, brass castings, or hard steel, tempering should be done
merely to take strains out of steel.

On ordinary machinery steel or nickel steel the temper can be drawn
to a dark blue or up to 900 deg.F. If the tool is of a special form
or character, the risk of melting or scaling the point cannot be
taken. In these cases the tool should be packed, but if there is
no packing equipment, a tool can be heated to as high heat as is
safe without risk to cutting edges, and cyanide or prussiate of
potash can be sprinkled over the face and then quenched in oil.

Some very adverse criticism may be heard on this point, but experience
has proved that such tools will stand up very nicely and be perfectly
free from scales or pipes. Where packing cannot be done, milling
cutters, and tools to be hardened all over, can be placed in muffled
furnace, brought to 2,220 deg. and quenched in oil. All such tools,
however, must be preheated slowly to 1,400 to 1,500 deg. then placed in
a high-speed furnace and brought up quickly. Do not soak high-speed
steel at high heats. Quench in oil.

We must bear in mind that the heating furnace is likely to expand
tools, therefore provision must be made to leave extra stock to
take care of such expansion. Tools with shanks such as counter
bores, taps, reamers, drills, etc., should be heated no further
than they are wanted hard, and quench in oil. If a forge is not
at hand and heating must be done, use a muffle furnace and cover
small shanks with a paste from fire clay or ground asbestos. Hollow
mills, spring threading dies, and large cutting tools with small
shanks should have the holes thoroughly packed or covered with
asbestos cement as far as they are wanted soft.





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