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Steel Making

ANNEALING can be done by heating to temperatures ranging from...

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

Heat-treating Department
The heat-treating department occupies an L-shaped building. ...

There is no mystery or secret about the proper annealing of d...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

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

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

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

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

The material used for all gears on the Liberty engine was sel...

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

Air-hardening Steels
These steels are recommended for boring, turning and planing...

Knowing What Takes Place
How are we to know if we have given a piece of steel the ver...

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

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

Making Steel Balls
Steel balls are made from rods or coils according to size, st...

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

The Influence Of Size
The size of the piece influences the physical properties obta...

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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