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Annealing Work
With the exception of several of the higher types of alloy s...

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

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

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

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

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

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

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

Standard Analysis
The selection of a standard analysis by the manufacturer is t...

Leeds And Northrup Optical Pyrometer
The principles of this very popular method of measuring tempe...

Take Time For Hardening
Uneven heating and poor quenching has caused loss of many ve...

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

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

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

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

Annealing Alloy Steel
The term alloy steel, from the steel maker's point of view, r...

Crucible Steel
Crucible steel is still made by melting material in a clay or...

Affinity Of Nickel Steel For Carbon
The carbon- and nickel-steel gears are carburized separately...



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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