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Preventing Carburizing By Copper-plating
Copper-plating has been found effective and must have a thick...

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

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...

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

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

Heat-treating Department
The heat-treating department occupies an L-shaped building. ...

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

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

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

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

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

Judging The Heat Of Steel
While the use of a pyrometer is of course the only way to hav...

Alloying Elements
Commercial steels of even the simplest types are therefore p...

For Milling Cutters And Formed Tools
FORGING.--Forge as before.--ANNEALING.--Place the steel in a ...

Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

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

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

Nickel
Nickel may be considered as the toughest among the non-rare a...

The Forging Of Steel
So much depends upon the forging of steel that this operation...



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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