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Steel Making

A combination of the characteristics of nickel and the charac...

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

Heat Treatment Of Milling Cutters Drills Reamers Etc
THE FIRE.--Gas and electric furnaces designed for high heats ...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

Impact Tests
Impact tests are of considerable importance as an indication ...

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

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

Carbon Steels For Different Tools
All users of tool steels should carefully study the different...

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

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

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

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Reheating for machine ability was done at 100 deg. less than ...

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

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

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Affinity Of Nickel Steel For Carbon
The carbon- and nickel-steel gears are carburized separately...

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

Judging The Heat Of Steel


While the use of a pyrometer is of course the only way to have
accurate knowledge as to the heat being used in either forging or
hardening steels, a color chart will be of considerable assistance
if carefully studied. These have been prepared by several of the
steel companies as a guide, but it must be remembered that the colors
and temperatures given are only approximate, and can be nothing

The Magnet Test.--The critical point can also be determined by
an ordinary horse-shoe magnet. Touch the steel with a magnet during
the heating and when it reaches the temperature at which steel fails
to attract the magnet, or in other words, loses its magnetism,
the critical point has been reached.

The work is heated up slowly in the furnace and the magnet applied
from time to time. The steel being heated will attract the magnet
until the heat reaches the critical point. The magnet is applied
frequently and when the magnet is no longer attracted, the piece
is at the lowest temperature at which it can be hardened properly.
Quenching slightly above this point will give a tool of satisfactory
hardness. The method applies only to carbon steels and will not
work for modern high-speed steels.

Next: Heat Treatment Of Gear Blanks

Previous: Hardening

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