Steelmaking.ca Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

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

Pyrometers For Molten Metal
Pyrometers for molten metal are connected to portable thermoc...

Annealing Method
Forgings which are too hard to machine are put in pots with ...

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

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

Sulphur
SULPHUR is another element (symbol S) which is always found i...

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

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

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

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

Annealing Alloy Steel
The term alloy steel, from the steel maker's point of view, r...

Heat-treating Equipment And Methods For Mass Production
The heat-treating department of the Brown-Lipe-Chapin Company...

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

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

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

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

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

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...

The Leeds And Northrup Potentiometer System
The potentiometer pyrometer system is both flexible and subst...

Piston Pin
The piston pin on an aviation engine must possess maximum res...



Annealing To Relieve Internal Stresses






Category: HARDENING CARBON STEEL FOR TOOLS

Work quenched from a high temperature and not afterward tempered
will, if complex in shape, contain many internal stresses which may
later cause it to break. They may be eased off by slight heating
without materially lessening the hardness of the piece. One way
to do this is to hold the piece over a fire and test it with a
moistened finger. Another way is to dip the piece in boiling water
after it has first been quenched in a cold bath. Such steps are
not necessary with articles which will afterward be tempered and
in which the strains are thus reduced.

In annealing steels the operation is similar to hardening, as far
as heating is concerned. The critical temperatures are the proper
ones for annealing as well as hardening. From this point on there
is a difference, for annealing consists in cooling as slowly as
possible. The slower the cooling the softer will be the steel.

Annealing may be done in the open air, in furnaces, in hot ashes
or lime, in powdered charcoal, in burnt bone, in charred leather
and in water. Open-air annealing will do as a crude measure in
cases where it is desired to take the internal stresses out of
a piece. Care must be taken in using this method that the piece
is not exposed to drafts or placed on some cold substance that
will chill it. Furnace annealing is much better and consists in
heating the piece in a furnace to the critical temperature and
then allowing the work and the furnace to cool together.

When lime or ashes are used as materials to keep air away from
the steel and retain the heat, they should be first heated to make
sure that they are dry. Powdered charcoal is used for high-grade
annealing, the piece being packed in this substance in an iron box
and both the work and the box raised to the critical temperature
and then allowed to cool slowly. Machinery steel may be annealed in
spent ground-bone that has been used in casehardening; but tool
steel must never be annealed in this way, as it will be injured
by the phosphorus contained in the bone. Charred leather is the
best annealing material for high-carbon steel, because it prevents
decarbonizing taking place.





Next: Double Annealing

Previous: Preventing Decarbonization Of Tool Steel



Add to Informational Site Network
Report
Privacy
ADD TO EBOOK


Viewed 4573