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Steel Making

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

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

Quenching The Work
In some operations case-hardened work is quenched from the bo...

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

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

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

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

Effect Of A Small Amount Of Copper In Medium-carbon Steel
This shows the result of tests by C. R. Hayward and A. B. Joh...

Rate Of Absorption
According to Guillet, the absorption of carbon is favored by ...

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

Crankshaft
The crankshaft was the most highly stressed part of the entir...

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

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

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

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

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

Process Of Carburizing
Carburizing imparts a shell of high-carbon content to a low-...

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...



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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