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

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

Flange Shields For Furnaces
Such portable flame shields as the one illustrated in Fig. 1...

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

Hardness Testing
The word hardness is used to express various properties of me...

Making Steel Balls
Steel balls are made from rods or coils according to size, st...

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

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

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

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

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

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

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

Heating
Although it is possible to work steels cold, to an extent de...

The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufa...

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

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

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

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



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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