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

Complete Calibration Of Pyrometers
For the complete calibration of a thermo-couple of unknown e...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

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

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

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

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

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

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

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

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

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

Double Annealing
Water annealing consists in heating the piece, allowing it to...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

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

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

Correction For Cold-junction Errors
The voltage generated by a thermo-couple of an electric pyrom...

Application Of Liberty Engine Materials To The Automotive Industry
The success of the Liberty engine program was an engineer...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...



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 3378