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Steel Making

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

Placing Of Pyrometers
When installing a pyrometer, care should be taken that it re...

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

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

Care In Annealing
Not only will benefits in machining be found by careful anne...

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

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

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

Hardening
Steel is hardened by quenching from above the upper critical....

A Chromium-cobalt Steel
The Latrobe Steel Company make a high-speed steel without tun...

Manganese
MANGANESE is a metal much like iron. Its chemical symbol is M...

Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

Annealing
ANNEALING can be done by heating to temperatures ranging from...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

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

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

Preventing Decarbonization Of Tool Steel
It is especially important to prevent decarbonization in such...

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

Highly Stressed Parts
The highly stressed parts on the Liberty engine consisted of ...



Sulphur






Category: COMPOSITION AND PROPERTIES OF STEEL

SULPHUR is another element (symbol S) which is always found in
steel in small quantities. Some sulphur is contained in the ore
from which the iron is smelted; more sulphur is introduced by the
coke and fuel used. Sulphur is very difficult to get rid of in
steel making; in fact the resulting metal usually contains a little
more than the raw materials used. Only the electric furnace is
able to produce the necessary heat and slags required to eliminate
sulphur, and as a matter of fact the sulphur does not go until
several other impurities have been eliminated. Consequently, an
electric steel with extremely low sulphur (0.02 per cent) is by
that same token a well-made metal.

Sulphur is of most trouble to rolling and forging operations when
conducted at a red heat. It makes steel tender and brittle at that
temperature--a condition known to the workmen as red-short. It
seems to have little or no effect upon the physical properties
of cold steel--at least as revealed by the ordinary testing
machines--consequently many specifications do not set any limit
on sulphur, resting on the idea that if sulphur is low enough not
to cause trouble to the manufacturer during rolling, it will not
cause the user any trouble.

Tool steel and other fine steels should be very low in sulphur,
preferably not higher than 0.03 per cent. Higher sulphur steels
(0.06 per cent, and even up to 0.10 per cent) have given very good
service for machine parts, but in general a high sulphur steel
is a suspicious steel. Screw stock is purposely made with up to
0.12 per cent sulphur and a like amount of phosphorus so it will
cut freely.

Manganese counteracts the detrimental effect of sulphur when present
in the steel to an amount at least five times the sulphur content.





Next: Phosphorus

Previous: Composition And Properties Of Steel



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