VIEW THE MOBILE VERSION of www.steelmaking.ca Informational Site Network Informational
Privacy
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

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

Annealing Method
Forgings which are too hard to machine are put in pots with ...

Oil-hardening Steel
Heat slowly and uniformly to 1,450 deg.F. and forge thorough...

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

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

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

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

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

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

Annealing
ANNEALING can be done by heating to temperatures ranging from...

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

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

Annealing Of Rifle Components At Springfield Armory
In general, all forgings of the components of the arms manufa...

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

Effect Of A Small Amount Of Copper In Medium-carbon Steel
This shows the result of tests by C. R. Hayward and A. B. Joh...

Critical Points
One of the most important means of investigating the properti...

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

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

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...



Refining The Grain






Category: CASE-HARDENING OR SURFACE-CARBURIZING

This is remedied by reheating the piece to a temperature slightly
above the critical temperature of the case, this temperature
corresponding ordinarily to that of steel having a carbon content
of 85 points, When this is again quenched, the temperature, which
has not been high enough to disturb the refined core, will have
closed the grain of the case and toughened it. So, instead of but
one heat and one quenching for this class of work, we have three
of each, although it is quite possible and often profitable to
omit the quenching after carburizing and allow the piece or pieces
and the case-carburizing box to cool together, as in annealing.
Sometimes another heat treatment is added to the foregoing, for
the purpose of letting down the hardness of the case and giving
it additional toughness by heating to a temperature between 300 deg.
and 500 deg.. Usually this is done in an oil bath. After this the piece
is allowed to cool.

It is possible to harden the surface of tool steel extremely hard
and yet leave its inner core soft and tough for strength, by a
process similar to case-hardening and known as pack-hardening.
It consists in using tool steel of carbon contents ranging from
60 to 80 points, packing this in a box with charred leather mixed
with wood charcoal and heating at a low-red heat for 2 or 3 hr.,
thus raising the carbon content of the exterior of the piece. The
article when quenched in an oil bath will have an extremely hard
exterior and tough core. It is a good scheme for tools that must
be hard and yet strong enough to stand abuse. Raw bone is never
used as a packing for this class of work, as it makes the cutting
edges brittle.





Next: Case-hardening Treatments For Various Steels

Previous: The Quenching Tank



Add to del.icio.us Add to Reddit Add to Digg Add to Del.icio.us Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network
Report
Privacy
SHAREADD TO EBOOK


Viewed 2863