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Steel Making

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

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

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

Properties Of Steel
Steels are known by certain tests. Early tests were more or l...

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

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

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

Oil-hardening Steel
Heat slowly and uniformly to 1,450 deg.F. and forge thorough...

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

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...

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

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

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

Manganese
MANGANESE is a metal much like iron. Its chemical symbol is M...

Highly Stressed Parts
The highly stressed parts on the Liberty engine consisted of ...

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

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

Carburizing Material
The simplest carburizing substance is charcoal. It is also th...

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

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...



Plant For Forging Rifle Barrels






Category: THE FORGING OF STEEL

The forging of rifle barrels in large quantities and heat-treating
them to meet the specifications demanded by some of the foreign
governments led Wheelock, Lovejoy & Company to establish a complete
plant for this purpose in connection with their warehouse in Cambridge,
Mass. This plant, designed and constructed by their chief engineer,
K. A. Juthe, had many interesting features. Many features of this
plant can be modified for other classes of work.




The stock, which came in bars of mill length, was cut off so as to
make a barrel with the proper allowances for trimming (Fig. 21).
They then pass to the forging or upsetting press in the adjoining
room. This press, which is shown in more detail in Fig. 22, handled
the barrels from all the heating furnaces shown. The men changed
work at frequent intervals, to avoid excessive fatigue.



Then the barrels were reheated in the continuous furnace, shown
in Fig. 23, and straightened before being tested.

The barrels were next tested for straightness. After the heat-treating,
the ends are ground, a spot ground on the enlarged end and each
barrel tested on a Brinell machine. The pressure used is 3,000 kg.,
or 6,614 lb., on a 10-millimeter ball, which is standard. Hardness
of 240 was desired.

The heat-treating of the rifle blanks covered four separate operations:
(1) Heating and soaking the steel above the critical temperature
and quenching in oil to harden the steel through to the center;
(2) reheating for drawing of temper for the purpose of meeting the
physical specifications; (3) reheating to meet the machine ability
test for production purposes; and (4) reheating to straighten the
blanks while hot.

A short explanation of the necessity for the many heats may be
interesting. For the first heat, the blanks were slowly brought
to the required heat, which is about 150 deg.F. above the critical
temperature. They are then soaked at a high heat for about 1 hr.
before quenching. The purpose of this treatment is to eliminate
any rolling or heat stresses that might be in the bars from mill
operations; also to insure a thorough even heat through a cross-section
of the steel. This heat also causes blanks with seams or slight
flaws to open up in quenching, making detection of defective blanks
very easy.

The quenching oil was kept at a constant temperature of 100 deg.F.,
to avoid subjecting the steel to shocks, thereby causing surface
cracks. The drawing of temper was the most critical operation and
was kept within a 10 deg. fluctuation. The degree of heat necessary
depends entirely on the analysis of the steel, there being a certain
variation in the different heats of steel as received from the mill.





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Previous: Chrome-nickel Steel



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