Informational Site NetworkInformational Site Network
Privacy
 
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

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

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

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...

Annealing Method
Forgings which are too hard to machine are put in pots with ...

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

Preventing Carburizing By Copper-plating
Copper-plating has been found effective and must have a thick...

The Leeds And Northrup Potentiometer System
The potentiometer pyrometer system is both flexible and subst...

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Tungsten
Tungsten, as an alloy in steel, has been known and used for a...

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

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

Heating
Although it is possible to work steels cold, to an extent de...

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

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 ...

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

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

Take Time For Hardening
Uneven heating and poor quenching has caused loss of many ve...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...



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 4630