Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

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

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

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

Case-hardening Treatments For Various Steels
Plain water, salt water and linseed oil are the three most co...

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

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...

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

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

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

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

Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

The Modern Hardening Room
A hardening room of today means a very different place from ...

SULPHUR is another element (symbol S) which is always found i...

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

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

Effect Of Different Carburizing Material
[Illustrations: FIGS. 33 to 37.] Each of these different p...

Sulphur is another impurity and high sulphur is even a greate...

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

Preparing Parts For Local Case-hardening
At the works of the Dayton Engineering Laboratories Company, ...

Complete Calibration Of Pyrometers


For the complete calibration
of a thermo-couple of unknown electromotive force, the new couple
may be checked against a standard instrument, placing the two bare
couples side by side in a suitable tube and taking frequent readings
over the range of temperatures desired.

If only one instrument, such as a millivoltmeter, is available,
and there is no standard couple at hand, the new couple may be
calibrated over a wide range of temperatures by the use of the following

Water, boiling point 212 deg.F.
Tin, under charcoal, freezing point 450 deg.F.
Lead, under charcoal, freezing point 621 deg.F.
Zinc, under charcoal, freezing point 786 deg.F.
Sulphur, boiling point 832 deg.F.
Aluminum, under charcoal, freezing point 1,216 deg.F.
Sodium chloride (salt), freezing point 1,474 deg.F.
Potassium sulphate, freezing point 1,958 deg.F.

A good practice is to make one pyrometer a standard; calibrate it
frequently by the melting-point-of-salt method, and each morning
check up every pyrometer in the works with the standard, making the
necessary corrections to be used for the day's work. By pursuing
this course systematically, the improved quality of the product
will much more than compensate for the extra work.

The purity of the substance affects its freezing or melting point.
The melting point of common salt is given in one widely used handbook
at 1,421 deg.F., although chemically pure sodium chloride melts at
1,474 deg.F. as shown above. A sufficient quantity for an extended
period should be secured. Test the melting point with a pyrometer
of known accuracy. Knowing this temperature it will be easy to
calibrate other pyrometers.

Next: Placing Of Pyrometers

Previous: Calibration Of Pyrometer With Common Salt

Add to Informational Site Network

Viewed 4619