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   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

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

Sulphur
Sulphur is another impurity and high sulphur is even a greate...

The Thermo-couple
With the application of the thermo-couple, the measurement of...

Gas Consumption For Carburizing
Although the advantages offered by the gas-fired furnace for ...

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Hardness Testing
The word hardness is used to express various properties of me...

Heat Treatment Of Steel
Heat treatment consists in heating and cooling metal at defin...

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

Application Of Liberty Engine Materials To The Automotive Industry
The success of the Liberty engine program was an engineer...

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

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

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

Phosphorus
PHOSPHORUS is an element (symbol P) which enters the metal fr...

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

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

Crucible Steel
Crucible steel is still made by melting material in a clay or...

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

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



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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