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Steel Making

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

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

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

Phosphorus
Phosphorus is one of the impurities in steel, and it has been...

Conclusions
Martien was probably never a serious contender for the honor ...

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

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

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

Double Annealing
Water annealing consists in heating the piece, allowing it to...

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

Nickel-chromium
A combination of the characteristics of nickel and the charac...

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

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

Connecting Rods
The material used for all connecting rods on the Liberty engi...

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

Preventing Decarbonization Of Tool Steel
It is especially important to prevent decarbonization in such...

Crankshaft
The crankshaft was the most highly stressed part of the entir...

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

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...

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



Pyrometry And Pyrometers






Category: PYROMETRY AND PYROMETERS

A knowledge of the fundamental principles of pyrometry, or the
measurement of temperatures, is quite necessary for one engaged
in the heat treatment of steel. It is only by careful measurement
and control of the heating of steel that the full benefit of a
heat-treating operation is secured.

Before the advent of the thermo-couple, methods of temperature
measurement were very crude. The blacksmith depended on his eyes
to tell him when the proper temperature was reached, and of course
the color appeared different on light or dark days. Cherry
to one man was orange to another, and it was therefore almost
impossible to formulate any treatment which could be applied by
several men to secure the same results.

One of the early methods of measuring temperatures was the iron
ball method. In this method, an iron ball, to which a wire was
attached, was placed in the furnace and when it had reached the
temperature of the furnace, it was quickly removed by means of
the wire, and suspended in a can containing a known quantity of
water; the volume of water being such that the heat would not cause
it to boil. The rise in temperature of the water was measured by a
thermometer, and, knowing the heat capacity of the iron ball and
that of the water, the temperature of the ball, and therefore the
furnace, could be calculated. Usually a set of tables was prepared
to simplify the calculations. The iron ball, however, scaled, and
changed in weight with repeated use, making the determinations
less and less accurate. A copper ball was often used to decrease
this change, but even that was subject to error. This method is
still sometimes used, but for uniform results, a platinum ball,
which will not scale or change in weight, is necessary, and the
cost of this ball, together with the slowness of the method, have
rendered the practice obsolete, especially in view of modern
developments in accurate pyrometry.





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Previous: Furnace Data



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