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Steel Making

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

Molybdenum
Molybdenum steels have been made commercially for twenty-five...

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

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

Effect Of Different Carburizing Material
[Illustrations: FIGS. 33 to 37.] Each of these different p...

Complete Calibration Of Pyrometers
For the complete calibration of a thermo-couple of unknown e...

Crucible Steel
Crucible steel is still made by melting material in a clay or...

Gears
The material used for all gears on the Liberty engine was sel...

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

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...

Sulphur
Sulphur is another impurity and high sulphur is even a greate...

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

Pyrometers For Molten Metal
Pyrometers for molten metal are connected to portable thermoc...

Pickling The Forgings
The forgings were then pickled in a hot solution of either ni...

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...



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.





Next: Cutting-off Steel From Bar

Previous: Quality And Structure



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