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Steel Making

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

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

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

Compensating Leads
By the use of compensating leads, formed of the same materia...

Ebbw Vale And The Bessemer Process
After his British Association address in August 1856, Besseme...

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

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

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

Highly Stressed Parts
The highly stressed parts on the Liberty engine consisted of ...

Silicon
SILICON is a very widespread element (symbol Si), being an es...

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

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

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is lar...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

Process Of Carburizing
Carburizing imparts a shell of high-carbon content to a low-...

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

Heat Treatment Of Steel
Heat treatment consists in heating and cooling metal at defin...



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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