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Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

The Forging Of Steel
So much depends upon the forging of steel that this operation...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

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

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

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

The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufa...

Lathe And Planer Tools
TO FORGE.--Gently warm the steel to remove any chill is parti...

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

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

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

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

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

Surface Carburizing
Carburizing, commonly called case-hardening, is the art of pr...

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

Annealing Work
With the exception of several of the higher types of alloy s...

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

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



Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer






Category: PYROMETRY AND PYROMETERS

For extremely high temperature, the optical pyrometer is
largely used. This is a comparative method. By means of the rheostat
the current through the lamp is adjusted until the brightness of
the filament is just equal to the brightness of the image produced
by the lens L, Fig. 123, whereupon the filament blends with or
becomes indistinguishable in the background formed by the image
of the hot object. This adjustment can be made with great accuracy
and certainty, as the effect of radiation upon the eye varies some
twenty times faster than does the temperature at 1,600 deg.F., and some
fourteen times faster at 3,400 deg.F. When a balance has been obtained,
the observer notes the reading of the milliammeter. The temperature
corresponding to the current is then read from a calibration curve
supplied with the instrument.



As the intensity of the light emitted at the higher temperatures
becomes dazzling, it is found desirable to introduce a piece of red
glass in the eye piece at R. This also eliminates any question
of matching colors, or of the observer's ability to distinguish
colors. It is further of value in dealing with bodies which do
not radiate light of the same composition as that emitted by a
black body, since nevertheless the intensity of radiation of any
one color from such bodies increases progressively in a definite
manner as the temperature rises. The intensity of this one color
can therefore be used as a measure of temperature for the body
in question. Figures 124 to 126 show the way it is read.





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Previous: Leeds And Northrup Optical Pyrometer



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