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Steel Making

Manganese
Manganese adds considerably to the tensile strength of steel,...

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

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

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

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

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

Molybdenum
Molybdenum steels have been made commercially for twenty-five...

Heavy Forging Practice
In heavy forging practice where the metal is being worked at...

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

Conclusions
Martien was probably never a serious contender for the honor ...

For Milling Cutters And Formed Tools
FORGING.--Forge as before.--ANNEALING.--Place the steel in a ...

The Quenching Tank
The quenching tank is an important feature of apparatus in c...

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

Uses Of The Various Tempers Of Carbon Tool Steel
DIE TEMPER.--No. 3: All kinds of dies for deep stamping, pres...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

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

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

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

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

Silicon
SILICON is a very widespread element (symbol Si), being an es...



Steel Worked In Austenitic State






Category: THE FORGING OF STEEL

As a general rule steel should
be worked when it is in the austenitic state. (See page 108.) It
is then soft and ductile.

As the steel is heated above the critical temperature the size of
the austenite crystals tends to grow rapidly. When forging starts,
however, these grains are broken up. The growth is continually
destroyed by the hammering, which should consequently be continued
down to the upper critical temperature when the austenite crystals
break up into ferrite and cementite. The size of the final grains
will be much smaller and hence a more uniform structure will result
if the mother austenite was also fine grained. A final steel
will be composed of pearlite; ferrite and pearlite; or cementite
and pearlite, according to the carbon content.

The ultimate object is to secure a fine, uniform grain throughout
the piece and this can be secured by uniform heating and by thoroughly
rolling it or working it at a temperature just down to its critical
point. If this is correctly done the fracture will be fine and
silky. Steel which has been overheated slightly and the forging
stopped at too high a temperature will show a granular fracture.
A badly overheated or burned steel will have iridescent colors
on a fresh fracture, it will be brittle both hot and cold, and
absolutely ruined.





Next: Steel Can Be Worked Cold

Previous: Heating



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