Informational Site NetworkInformational Site Network
Privacy
 
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

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

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

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

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

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

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

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

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

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

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

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

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

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

Mushet And Bessemer
That Mushet was "used" by Ebbw Vale against Bessemer is, perh...

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

Preventing Carburizing By Copper-plating
Copper-plating has been found effective and must have a thick...

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

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...

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

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...



Carburizing Material






Category: CASE-HARDENING OR SURFACE-CARBURIZING

The simplest carburizing substance is charcoal. It is also the
slowest, but is often used mixed with something that will evolve
large volumes of carbon monoxide or hydrocarbon gas on being heated.
A great variety of materials is used, a few of them being charcoal
(both wood and bone), charred leather, crushed bone, horn, mixtures
of charcoal and barium carbonate, coke and heavy oils, coke treated
with alkaline carbonates, peat, charcoal mixed with common salt,
saltpeter, resin, flour, potassium bichromate, vegetable fibre,
limestone, various seed husks, etc. In general, it is well to avoid
complex mixtures.

H. L. Heathcote, on analyzing seventeen different carburizers, found
that they contained the following ingredients:

Per cent
Moisture 2.68 to 26.17
Oil 0.17 to 20.76
Carbon (organic) 6.70 to 54.19
Calcium phosphate 0.32 to 74.75
Calcium carbonate 1.20 to 11.57
Barium carbonate nil to 42.00
Zinc oxide nil to 14.50
Silica nil to 8.14
Sulphates (SO3) trace to 3.45
Sodium chloride nil to 7.88
Sodium carbonate nil to 40.00
Sulphides (S) nil to 2.80

Carburizing mixtures, though bought by weight, are used by volume,
and the weight per cubic foot is a big factor in making a selection.
A good mixture should be porous, so that the evolved gases, which
should be generated at the proper temperature, may move freely
around the steel objects being carburized; should be a good conductor
of heat; should possess minimum shrinkage when used; and should
be capable of being tamped down.

Many secret mixtures are sold, falsely claimed to be able to
convert inferior metal into crucible tool steel grade. They are
generally nothing more than mixtures of carbonaceous and cyanogen
compounds possessing the well-known carburizing properties of those
substances.





Next: Quenching

Previous: Rate Of Absorption



Add to del.icio.us Add to Reddit Add to Digg Add to Del.icio.us Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network
Report
Privacy
SHAREADD TO EBOOK


Viewed 4811