Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

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

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

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

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

The forgings can be hardened by cooling in still air or quen...

Steel Before The 1850's
In spite of a rapid increase in the use of machines and the ...

Heat Treatment Of Milling Cutters Drills Reamers Etc
THE FIRE.--Gas and electric furnaces designed for high heats ...

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

Ebbw Vale And The Bessemer Process
After his British Association address in August 1856, Besseme...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

Furnace Data
In order to give definite information concerning furnaces, fu...

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

Effect Of A Small Amount Of Copper In Medium-carbon Steel
This shows the result of tests by C. R. Hayward and A. B. Joh...

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

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

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

Quenching The Work
In some operations case-hardened work is quenched from the bo...

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

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.

Next: Pyrometers

Previous: Furnace Data

Add to Informational Site Network

Viewed 4807