Steelmaking.ca Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

Annealing Alloy Steel
The term alloy steel, from the steel maker's point of view, r...

Phosphorus
PHOSPHORUS is an element (symbol P) which enters the metal fr...

Hardness Testing
The word hardness is used to express various properties of me...

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

Quenching The Work
In some operations case-hardened work is quenched from the bo...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

Heat Treatment Of Lathe Planer And Similar Tools
FIRE.--For these tools a good fire is one made of hard foundr...

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

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

The Quenching Tank
The quenching tank is an important feature of apparatus in c...

Care In Annealing
Not only will benefits in machining be found by careful anne...

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

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

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

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

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...

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

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

Preventing Cracks In Hardening
The blacksmith in the small shop, where equipment is usually ...

Cutting-off Steel From Bar
To cut a piece from an annealed bar, cut off with a hack saw,...



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 Informational Site Network
Report
Privacy
ADD TO EBOOK


Viewed 6486