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Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

Drop Forging Dies
The kind of steel used in the die of course influences the he...

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

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

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

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

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

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

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

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

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

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

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

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

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

The Theory Of Tempering
Steel that has been hardened is generally harder and more br...

Complete Calibration Of Pyrometers
For the complete calibration of a thermo-couple of unknown e...

Bessemer Process
The bessemer process consists of charging molten pig iron int...

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

Making Steel Balls
Steel balls are made from rods or coils according to size, st...



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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