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Steel Making

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

A combination of the characteristics of nickel and the charac...

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

The Electric Process
The fourth method of manufacturing steel is by the electric f...

Carbon Steels For Different Tools
All users of tool steels should carefully study the different...

The Thermo-couple
With the application of the thermo-couple, the measurement of...

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

Chromium when alloyed with steel, has the characteristic func...

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

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

Heat-treating Equipment And Methods For Mass Production
The heat-treating department of the Brown-Lipe-Chapin Company...

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

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

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

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

Highly Stressed Parts
The highly stressed parts on the Liberty engine consisted of ...

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

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

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

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