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Case-hardening Treatments For Various Steels
Plain water, salt water and linseed oil are the three most co...

Gears
The material used for all gears on the Liberty engine was sel...

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

Chromium
Chromium when alloyed with steel, has the characteristic func...

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

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

Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

Impact Tests
Impact tests are of considerable importance as an indication ...

Phosphorus
PHOSPHORUS is an element (symbol P) which enters the metal fr...

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

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

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

Heat Treatment Of Lathe Planer And Similar Tools
FIRE.--For these tools a good fire is one made of hard foundr...

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

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

Critical Points
One of the most important means of investigating the properti...

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

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

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



Introduction Of Carbon






Category: CASE-HARDENING OR SURFACE-CARBURIZING

The matter to which these notes are primarily directed is the
introduction of carbon into the case of the article to be hardened.
In the first place the chances of success are increased by selecting
as few brands of steel as practicable to cover the requirements of
each component of the mechanism. The hardener is then able to become
accustomed to the characteristics of that particular material, and
after determining the most suitable treatment for it no further
experimenting beyond the usual check-test pieces is necessary.

Although a certain make of material may vary in composition from
time to time the products of a manufacturer of good steel can be
generally relied upon, and it is better to deal directly with him
than with others.

In most cases the case-hardening steels can be chosen from the
following: (1) Case-hardening mild steel of 0.20 per cent carbon;
(2) case-hardening 3-1/2 per cent nickel steel; (3) case-hardening
nickel-chromium steel; (4) case-hardening chromium vanadium. After
having chosen a suitable steel it is best to have the sample analyzed
by reliable chemists and also to have test pieces machined and pulled.

To prepare samples for analysis place a sheet of paper on the table
of a drilling machine, and with a 3/8-in. diameter drill, machine
a few holes about 3/8 in. deep in various parts of the sample bar,
collecting about 3 oz. of fine drillings free from dust. This can be
placed in a bottle and dispatched to the laboratory with instructions
to search for carbon, silicon, manganese, sulphur, phosphorus and
alloys. The results of the different tests should be carefully
tabulated, and as there would most probably be some variation an
average should be made as a fair basis of each element present,
and the following tables may be used with confidence when deciding
if the material is reliable enough to be used.

TABLE 16.--CASE-HARDENING MILD STEEL OF 0.20 PER CENT CARBON

Carbon 0.15 to 0.25 per cent
Silicon Not over 0.20 per cent
Manganese 0.30 to 0.60 per cent
Sulphur Not over 0.04 per cent
Phosphorus Not over 0.04 per cent

A tension test should register at least 60,000 lb. per square inch.

TABLE 17.--CASE-HARDENING 3-1/2 PER CENT NICKEL STEEL

Carbon 0.12 to 0.20 per cent
Manganese 0.65 per cent
Sulphur Not over 0.045 per cent
Phosphorus Not over 0.04 per cent
Nickel 3.25 to 3.75 per cent

TABLE 18.--CASE-HARDENING NICKEL CHROMIUM STEEL

Carbon 0.15 to 0.25 per cent
Manganese 0.50 to 0.80 per cent
Sulphur Not over 0.045 per cent
Phosphorus Not over 0.04 per cent
Nickel 1 to 1.5 per cent
Chromium 0.45 to 0.75 per cent

TABLE 19.--CASE-HARDENING CHROMIUM VANADIUM STEEL

Carbon Not over 0.25 per cent
Manganese 0.50 to 0.85 per cent
Sulphur Not over 0.04 per cent
Phosphorus Not over 0.04 per cent
Chromium 0.80 to 1.10 per cent
Vanadium Not less than 0.15 per cent

Having determined what is required we now proceed to inquire into
the question of carburizing, which is of vital importance.





Next: Using Illuminating Gas

Previous: The Penetration Of Carbon



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