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Steel Making

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

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

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

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

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

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

Annealing Method
Forgings which are too hard to machine are put in pots with ...

High-carbon Machinery Steel
The carbon content of this steel is above 30 points and is ha...

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

Surface Carburizing
Carburizing, commonly called case-hardening, is the art of pr...

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

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Correction For Cold-junction Errors
The voltage generated by a thermo-couple of an electric pyrom...

Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

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

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...



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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