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Steel Making

Silicon
SILICON is a very widespread element (symbol Si), being an es...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

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

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

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

Conclusions
Martien was probably never a serious contender for the honor ...

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

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

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

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

Heat Treatment Of Steel
Heat treatment consists in heating and cooling metal at defin...

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

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

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

Flange Shields For Furnaces
Such portable flame shields as the one illustrated in Fig. 1...

Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is lar...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

Carburizing Material
The simplest carburizing substance is charcoal. It is also th...

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

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



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



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