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Steel Making

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

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

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

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

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

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

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

There is no mystery or secret about the proper annealing of d...

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

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

This steel like any other steel when distorted by cold worki...

Sulphur is another impurity and high sulphur is even a greate...

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

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

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...

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

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

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

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

Knowing What Takes Place


How are we to know if we have given a
piece of steel the very best possible treatment?

The best method is by microscopic examination of polished and etched
sections, but this requires a certain expense for laboratory equipment
and upkeep, which may prevent an ordinary commercial plant from
attempting such a refinement. It is highly recommended that any
firm that has any large amount of heat treatment to do, install
such an equipment, which can be purchased for from $250 to $500.
Its intelligent use will save its cost in a very short time.

The other method is by examination of fractures of small test bars.
Steel heated to its correct temperatures will show the finest possible
grain, whereas underheated steel has not had its grain structure
refined sufficiently, and so will not be at its best. On the other
hand, overheated steel will have a coarser structure, depending
on the extent of overheating.

To determine the proper quenching temperature of any particular
grade of steel it is only necessary to heat pieces to various
temperatures not more than 20 deg.C. (36 deg.F.) apart, quench in water,
break them, and examine the fractures. The temperature producing
the finest grain should be used for annealing and hardening.

Similarly, to determine tempering temperatures, several pieces
should be hardened, then tempered to various degrees, and cooled
in air. Samples, say six, reheated to temperatures varying by 100 deg.
from 300 to 800 deg.C. will show a considerable range of properties,
and the drawing temperature of the piece giving the desired results
can be used.

For drawing tempers up to 500 deg.F. oil baths of fresh cotton seed
oil can be safely and satisfactorily used. For higher temperature
a bath of some kind of fused salt is recommended.

Next: Hints For Tool Steel Users

Previous: Temperatures To Use

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