| Specialized
tasks:
Shrink
fitting: The
process of fitting a piece into a hole that is smaller than the
piece itself. This is done by cooling the insert in liquid Nitrogen,
causing it to shrink slightly, and heating the other piece, causing
it to expand. The parts are then assembled. When the assembled parts reach
room temperature, they will be frozen together.
Vacuum
Hardening:
County
has three vacuum furnaces used primarily for hardening of tool
steels and stainless steels, brazing and solution annealing.
Our
largest furnace is capable of processing loads up to 1000 pounds.
Small parts requiring hardening usually have a one-day turn-around
time.

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| This
is
a load of tool steel ready to unload from our vacuum furnace
after hardening. |
This
is a load of stainless steel shafts racked in a vertical position
and ready for heat treatment. |
Straightening:
Unfortunately,
distortion is an unavoidable product of heat treating. This may
be caused by any number of factors:
- Choice of steel
relevant to the heat treatment required
- Severity of machining
- Defects in steel
Depending
on each individual's job requirements, our Straightening Department
uses hot and cold straightening, peen hammering or spot straightening
to bring the product within finishing tolerances.
Nitriding
CHT
operator loads a plastic injection molding screw to be nitrided
into one of our two nitriding furnaces. CHT's nitriding furnaces
are able to process parts up to 115 inches long and 38 inches
in diameter, including stainless steel.

Nitride
Furnace |

Nitride
Furnace |
Neutral
Hardening:
Need
Localized hardening text.....
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A large alloy plate is transferred from our atmosphere pit
furnace to an oil quench bath. |
Flame
Hardening:
Flame
hardening is a long-used effective form of localized hardening.
Fast and efficient, this method requires an experienced eye to
run the job. County has over 100 years of combined experience
to ensure maximum quality and customer satisfaction.
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First and second picture is a gear being torch-heated. The
third is the gear being oil-quenched.
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Inspection
Department :
Here at County Heat Treat we are able to perform Rockwell and Brinell hardness
testing as well as micro hardness testing.
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Here is a picture of (Steve) an inspector performing a rockwell
hardness test.
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Brazing:
In our four vacuum
furnaces we vacuum braze using copper or nickel compounds.
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These are pictures of parts that were copper-brazed in a vacuum
furnace. |
Cleaning: The finishing touch
When
desired, abrasive cleaning is performed in a variety of ways.
Heavy-duty scale and discoloration are removed through sandblasting
on a 72" table blaster. Large volumes of small parts are
tumble sandblasted. Other methods of cleaning include glass beading
and aluminum oxide in sandblast cabinets.

A
heat-treated component before and after glass bead treatment
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Before
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After
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