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Steel Making

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

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

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

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

Compensating Leads
By the use of compensating leads, formed of the same materia...

Hardening Carbon Steel For Tools
For years the toolmaker had full sway in regard to make of st...

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

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

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

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

Temperatures To Use
As soon as the temperature of the steel reaches 100 deg.C. (...

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Critical Points
One of the most important means of investigating the properti...

Effect Of Different Carburizing Material
[Illustrations: FIGS. 33 to 37.] Each of these different p...

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

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

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

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

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

Carburizing Material
The simplest carburizing substance is charcoal. It is also th...



Silicon






Category: COMPOSITION AND PROPERTIES OF STEEL

SILICON is a very widespread element (symbol Si), being an essential
constituent of nearly all the rocks of the earth. It is similar to
carbon in many of its chemical properties; for instance it burns
very readily in oxygen, and consequently native silicon is unknown--it
is always found in combination with one or more other elements.
When it bums, each atom of silicon unites with two atoms of oxygen
to form a compound known to chemists as silica (SiO2), and to the
small boy as sand and agate.

Iron ore (an oxide of iron) contains more or less sand and dirt
mixed in it when it is mined, and not only the iron oxide but also
some of the silicon oxide is robbed of its oxygen by the smelting
process. Pig iron--the product of the blast furnace--therefore
contains from 1 to 3 per cent of silicon, and some silicon remains
in the metal after it has been purified and converted into steel.

However, silicon, as noted above, burns very readily in oxygen,
and this property is of good use in steel making. At the end of
the steel-making process the metal contains more or less oxygen,
which must be removed. This is sometimes done (especially in the
so-called acid process) by adding a small amount of silicon to
the hot metal just before it leaves the furnace, and stirring it
in. It thereupon abstracts oxygen from the metal wherever it finds
it, changing to silica (SiO2) which rises and floats on the surface
of the cleaned metal. Most of the silicon remaining in the metal
is an excess over that which is required to remove the dangerous
oxygen, and the final analysis of many steels show enough silicon
(from 0.20 to 0.40) to make sure that this step in the manufacture
has been properly done.





Next: Manganese

Previous: Phosphorus



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