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

Steel Making

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

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

Drop Forging Dies
The kind of steel used in the die of course influences the he...

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

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

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

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

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

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

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

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

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

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

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...

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

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

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



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 6320