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Steel Making

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

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

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

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

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

Steel Before The 1850's
In spite of a rapid increase in the use of machines and the ...

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Carbon Steels For Different Tools
All users of tool steels should carefully study the different...

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

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

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

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

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

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

Hardening
The forgings can be hardened by cooling in still air or quen...

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

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

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

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



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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