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Steel Making

The Packing Department
In Fig. 56 is shown the packing pots where the work is packe...

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

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

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

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

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

Furnace Data
In order to give definite information concerning furnaces, fu...

Annealing
There is no mystery or secret about the proper annealing of d...

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

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

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

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

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

Connecting Rods
The material used for all connecting rods on the Liberty engi...

Alloying Elements
Commercial steels of even the simplest types are therefore p...

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

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

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

Complete Calibration Of Pyrometers
For the complete calibration of a thermo-couple of unknown e...

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...



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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