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Steel Making

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

Steel is hardened by quenching from above the upper critical....

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

Heavy Forging Practice
In heavy forging practice where the metal is being worked at...

Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

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

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

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

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

Nickel may be considered as the toughest among the non-rare a...

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

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

Cutting-off Steel From Bar
To cut a piece from an annealed bar, cut off with a hack saw,...

Properties Of Alloy Steels
The following table shows the percentages of carbon, manganes...

Effects Of Proper Annealing
Proper annealing of low-carbon steels causes a complete solu...

Reheating for machine ability was done at 100 deg. less than ...

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

MANGANESE is a metal much like iron. Its chemical symbol is M...

High-carbon Machinery Steel
The carbon content of this steel is above 30 points and is ha...

Hardening Operation


Hardening a gear is accomplished as follows:
The gear is taken from the furnace by the furnaceman and placed in
the lower die, surrounding the centering jaws, as shown at H in
Fig. 62 and C in Fig. 63. Air is then turned into the cylinder
D, and the piston rod E, the die carrier B, the top die F
and the expander G descend. The pilot H enters a hole in the
center of the lower die, and the expander G enters the centering
jaws I, causing them to expand and center the gear C in the
lower die. On further advance of the piston rod E, the expander
G is forced upward against the pressure of the springs J and
the upper die F comes in contact with the upper surface of the
gear. Further downward movement of the dies, which now clamp the
work securely, overcomes the resistance of the pressure weight
K (which normally keeps up the plunger A), and the gear is
submerged in the oil. The quenching oil is circulated through a
cooling system outside the building and enters the tempering machine
through the inlet pipe L. When the machine is in the position
shown, the oil passes out through the ports M in the lower plunger
to the outer reservoir N, passing to the cooling system by way of
the overflow O. When the lower plunger A is forced downward,
the ports M are automatically closed and the cool quenching oil
from the inlet pipe L, having no other means of escape, passes
through the holes in the lower die and the grooves in the upper,
circulating in contact with the surfaces of the gear and passes to
the overflow. When the air pressure is released, the counterweights
return the parts to the positions shown in Fig. 63, and the operator
removes the gear.

The gear comes out uniformly hard all over and of the same degree of
hardness as when tempered in an open tank. The output of the machine
depends on the amount of metal to be cooled, but will average from
8 to 16 per hour. Each machine is served by one man, two furnaces
being required to heat the work. A slight excess of oil is used
in the firing of the furnaces to give a reducing atmosphere and
to avoid scale.

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