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Steel Making

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

Preventing Decarbonization Of Tool Steel
It is especially important to prevent decarbonization in such...

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

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

Annealing Work
With the exception of several of the higher types of alloy s...

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

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

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

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

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

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

Bessemer Process
The bessemer process consists of charging molten pig iron int...

Compensating Leads
By the use of compensating leads, formed of the same materia...

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

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

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

Suggestions For Handling High-speed Steels
The following suggestions for handling high-speed steels are ...

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

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

High Speed Steel
For centuries the secret art of making tool steel was handed ...

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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