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Steel Making

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

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

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

Machineability
Reheating for machine ability was done at 100 deg. less than ...

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

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

The Packing Department
In Fig. 56 is shown the packing pots where the work is packe...

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

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

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

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

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

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

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

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

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

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



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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