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

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

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

Surface Carburizing
Carburizing, commonly called case-hardening, is the art of pr...

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

Gas Consumption For Carburizing
Although the advantages offered by the gas-fired furnace for ...

Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring tempe...

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...

Alloying Elements
Commercial steels of even the simplest types are therefore p...

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

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

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

Steel Before The 1850's
In spite of a rapid increase in the use of machines and the ...

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

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

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...



Case-hardening Treatments For Various Steels






Category: CASE-HARDENING OR SURFACE-CARBURIZING

Plain water, salt water and linseed oil are the three most common
quenching materials for case-hardening. Water is used for ordinary
work, salt water for work which must be extremely hard on the surface,
and oil for work in which toughness is the main consideration. The
higher the carbon of the case, the less sudden need the quenching
action take hold of the piece; in fact, experience in case-hardening
work gives a great many combinations of quenching baths of these
three materials, depending on their temperatures. Thin work, highly
carbonized, which would fly to pieces under the slightest blow if
quenched in water or brine, is made strong and tough by properly
quenching in slightly heated oil. It is impossible to give any
rules for the temperature of this work, so much depending on the
size and design of the piece; but it is not a difficult matter to
try three or four pieces by different methods and determine what
is needed for best results.

The alloy steels are all susceptible of case-hardening treatment;
in fact, this is one of the most important heat treatments for such
steels in the automobile industry. Nickel steel carburizes more
slowly than common steel, the nickel seeming to have the effect
of slowing down the rate of penetration. There is no cloud without
its silver lining, however, and to offset this retardation, a single
treatment is often sufficient for nickel steel; for the core is not
coarsened as much as low-carbon machinery steel and thus ordinary
work may be quenched on the carburizing heat. Steel containing
from 3 to 3.5 per cent of nickel is carburized between 1,650 and
1,750 deg.F. Nickel steel containing less than 25 points of carbon,
with this same percentage of nickel, may be slightly hardened by
cooling in air instead of quenching.

Chrome-nickel steel may be case-hardened similarly to the method just
described for nickel steel, but double treatment gives better results
and is used for high-grade work. The carburizing temperature is the
same, between 1,650 and 1,750 deg.F., the second treatment consisting
of reheating to 1,400 deg. and then quenching in boiling salt water,
which gives a hard surface and at the same time prevents distortion
of the piece. The core of chrome-nickel case-hardened steel, like
that of nickel steel, is not coarsened excessively by the first
heat treatment, and therefore a single heating and quenching will
suffice.





Next: Carburizing By Gas

Previous: Refining The Grain



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 6088