VIEW THE MOBILE VERSION of www.steelmaking.ca Informational Site Network Informational
Privacy
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Silicon
SILICON is a very widespread element (symbol Si), being an es...

Gears
The material used for all gears on the Liberty engine was sel...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

Sulphur
Sulphur is another impurity and high sulphur is even a greate...

Chromium
Chromium when alloyed with steel, has the characteristic func...

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

Correction By Zero Adjustment
Many pyrometers are supplied with a zero adjuster, by means ...

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

Highly Stressed Parts
The highly stressed parts on the Liberty engine consisted of ...

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

The Modern Hardening Room
A hardening room of today means a very different place from ...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

Protectors For Thermo-couples
Thermo-couples must be protected from the danger of mechanica...

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

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

Crankshaft
The crankshaft was the most highly stressed part of the entir...

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



Highly Stressed Parts






Category: APPLICATION OF LIBERTY ENGINE MATERIALS TO THE AUTOMOTIVE INDUSTRY

The highly stressed parts on the Liberty engine consisted of the
connecting-rod bolt, the main-bearing bolt, the propeller-hub key,
etc. The material used for parts of this type was selected at the
option of the manufacturer from standard S. A. E. steels, the
composition of which are given in Table 11.

TABLE 11.--COMPOSITION OF S. A. E. STEELS Nos. 2,330, 3,135 AND 6,130

Steel No 2,330 3,135 6,130
Carbon, minimum 0.250 0.300 0.250
Carbon, maximum 0.350 0.400 0.450
Manganese, minimum 0.500 0.500 0.500
Manganese, maximum 0.800 0.800 0.800
Phosphorus, maximum 0.045 0.040 0.040
Sulphur, maximum 0.045 0.045 0.045
Nickel, minimum 3.250 1.000
Nickel, maximum 3.750 1.500
Chromium, minimum 0.450 0.800
Chromium, maximum 0.750 1.100
Vanadium, minimum 0.150

All highly stressed parts on the Liberty engine must show, after
heat treatment, the following minimum physical properties: Elastic
limit, 100,000 lb. per square inch; elongation in 2 in., 16 per
cent; reduction of area, 45 per cent; scleroscope hardness, 40
to 50.

The heat treatment employed to obtain these physical properties
consisted in quenching from a temperature of 1,525 to 1,575 deg.F., in
oil, followed by tempering at a temperature of from 925 to 975 deg.F.

Due to the extremely fine limits used on all threaded parts for
the Liberty engine, a large percentage of rejection was due to
warpage and scaling of parts. To eliminate this objection, many
of the Liberty engine builders adopted the use of heat-treated
and cold-drawn alloy steel for their highly stressed parts. On
all sizes up to and including 3/8 in. in diameter, the physical
properties were secured by merely normalizing the hot-rolled bars
by heating to a temperature of from 1,525 to 1,575 deg.F., and cooling
in air, followed by the usual cold-drawing reductions. For parts
requiring stock over 3/8 in. in diameter, the physical properties
desired were obtained by quenching and tempering the hot-rolled bars
before cold-drawing. It is the opinion that the use of heat-treated
and cold-drawn bars is very good practice, provided proper inspection
is made to guarantee the uniformity of heat treatment and, therefore,
the uniformity of the physical properties of the finished parts.

The question has been asked many times by different manufacturers, as
to which alloy steel offers the best machineability when heat-treated
to a given Brinell hardness. The general consensus of opinion among
the screw-machine manufacturers is that S. A. E. No. 6,130 steel
gives the best machineability and that S. A. E. No. 2,330 steel
would receive second choice of the three specified.

In the finishing of highly stressed parts for aviation engines,
extreme care must be taken to see that all tool marks are eliminated,
unless they are parallel to the axis of strain, and that proper
radii are maintained at all changes of section. This is of the
utmost importance to give proper fatigue resistance to the part
in question.





Next: Gears

Previous: Carbon-steel Forgings



Add to del.icio.us Add to Reddit Add to Digg Add to Del.icio.us Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network
Report
Privacy
SHAREADD TO EBOOK


Viewed 3173