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Steel Making

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Preparing Parts For Local Case-hardening
At the works of the Dayton Engineering Laboratories Company, ...

Hardening Carbon Steel For Tools
For years the toolmaker had full sway in regard to make of st...

Preventing Cracks In Hardening
The blacksmith in the small shop, where equipment is usually ...

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

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

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

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

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

Heat-treating Department
The heat-treating department occupies an L-shaped building. ...

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

Nickel-chromium
A combination of the characteristics of nickel and the charac...

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

Mushet And Bessemer
That Mushet was "used" by Ebbw Vale against Bessemer is, perh...

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

Ebbw Vale And The Bessemer Process
After his British Association address in August 1856, Besseme...

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

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



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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