Heat Treatment Of Gear Blanks
Category: HEAT TREATMENT OF STEEL
This section is based on a paper read before the American Gear
Manufacturers' Association at White Sulphur Springs, W. Va., Apr.
Great advancement has been made in the heat treating and hardening of
gears. In this advancement the chemical and metallurgical laboratory
have played no small part. During this time, however, the condition
of the blanks as they come to the machine shop to be machined has
not received its share of attention.
There are two distinct types of gears, both types having their
champions, namely, carburized and heat-treated. The difference
between the two in the matter of steel composition is entirely in
the carbon content, the carbon never running higher than 25-point
in the carburizing type, while in the heat-treated gears the carbon
is seldom lower than 35-point. The difference in the final gear
is the hardness. The carburized gear is file hard on the surface,
with a soft, tough and ductile core to withstand shock, while the
heat-treated gear has a surface that can be touched by a file with
a core of the same hardness as the outer surface.
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