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

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

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

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

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

Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

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

Sulphur is another impurity and high sulphur is even a greate...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Impact Tests
Impact tests are of considerable importance as an indication ...

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

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

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

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

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

Care In Annealing
Not only will benefits in machining be found by careful anne...

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

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

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

Plant For Forging Rifle Barrels


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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