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Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

Heat-treating Equipment And Methods For Mass Production
The heat-treating department of the Brown-Lipe-Chapin Company...

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

Connecting Rods
The material used for all connecting rods on the Liberty engi...

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

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

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

The Electric Process
The fourth method of manufacturing steel is by the electric f...

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

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

Hardening
The forgings can be hardened by cooling in still air or quen...

Nickel-chromium
A combination of the characteristics of nickel and the charac...

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

Hardness Testing
The word hardness is used to express various properties of me...

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

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

Hardening
Steel is hardened by quenching from above the upper critical....

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

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



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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