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Quality And Structure
The quality of high-speed steel is dependent to a very great ...

Separating The Work From The Compound
During the pulling of the heat, the pots are dumped upon a ca...

Hardening
Steel is hardened by quenching from above the upper critical....

Annealing In Bone
Steel and cast iron may both be annealed in granulated bone. ...

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

Nickel
Nickel may be considered as the toughest among the non-rare a...

Brown Automatic Signaling Pyrometer
In large heat-treating plants it has been customary to mainta...

The Influence Of Size
The size of the piece influences the physical properties obta...

The Forging Of Steel
So much depends upon the forging of steel that this operation...

Conclusions
Martien was probably never a serious contender for the honor ...

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

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

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

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

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

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

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

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

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Optical System And Electrical Circuit Of The Leeds & Northrup Optical Pyrometer
For extremely high temperature, the optical pyrometer is lar...



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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