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Machineability
Reheating for machine ability was done at 100 deg. less than ...

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

Quenching Tool Steel
To secure proper hardness, the cooling of quenching of steel ...

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

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

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

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

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

Hardening
The forgings can be hardened by cooling in still air or quen...

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

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

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

Bessemer Process
The bessemer process consists of charging molten pig iron int...

Steel Before The 1850's
In spite of a rapid increase in the use of machines and the ...

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

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

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

The Thermo-couple
With the application of the thermo-couple, the measurement of...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...



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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