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Steel Making

Knowing What Takes Place
How are we to know if we have given a piece of steel the ver...

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

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

Suggestions For Handling High-speed Steels
The following suggestions for handling high-speed steels are ...

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

Oil-hardening Steel
Heat slowly and uniformly to 1,450 deg.F. and forge thorough...

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

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

Preventing Cracks In Hardening
The blacksmith in the small shop, where equipment is usually ...

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...

Judging The Heat Of Steel
While the use of a pyrometer is of course the only way to hav...

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

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

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

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

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

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

Pickling The Forgings
The forgings were then pickled in a hot solution of either ni...

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



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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