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Steel Making

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

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

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

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

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

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

Annealing Alloy Steel
The term alloy steel, from the steel maker's point of view, r...

Temperatures To Use
As soon as the temperature of the steel reaches 100 deg.C. (...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Annealing Work
With the exception of several of the higher types of alloy s...

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

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

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

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

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

A Chromium-cobalt Steel
The Latrobe Steel Company make a high-speed steel without tun...

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Rate Of Absorption
According to Guillet, the absorption of carbon is favored by ...

The Modern Hardening Room
A hardening room of today means a very different place from ...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...



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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