Gears

: APPLICATION OF LIBERTY ENGINE MATERIALS TO THE AUTOMOTIVE INDUSTRY
: The Working Of Steel

The material used for all gears on the Liberty engine was selected

at the option of the manufacturer from the following standard S.

A. E. steels, the composition of which are given in Table 12,



TABLE 12.--COMPOSITION OF STEELS NOS. X-3,340 AND 6,140



Steel No X-3,340 6,140

Carbon, minimum 0.350 0.350

Carbon, maximum 0.450 0.450

Manganese
minimum 0.450 0.500

Manganese, maximum 0.750 0.800

Phosphorus, maximum 0.040 0.040

Sulphur, maximum 0.045 0.045

Nickel, minimum 2.750

Nickel, maximum 3.250

Chromium, minimum 0.700 0.800

Chromium, maximum 0.950 1.100

Vanadium, minimum 0.150



All gears were heat-treated to a scleroscope hardness of from 55

to 55. The heat treatment used to secure this hardness consisted

in quenching the forgings from a temperature of 1,550 to 1,600 deg.F.

in oil and annealing for good machineability at a temperature of

from 1,300 to 1,350 deg.F. Forgings treated in this manner showed a

Brinell hardness of from 177 to 217.



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