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Steel Making

Crucible Steel
Crucible steel is still made by melting material in a clay or...

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

The Packing Department
In Fig. 56 is shown the packing pots where the work is packe...

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

Annealing Method
Forgings which are too hard to machine are put in pots with ...

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

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

Molybdenum
Molybdenum steels have been made commercially for twenty-five...

Short Method Of Treatment
In the new method, the packed pots are run into the case-har...

Double Annealing
Water annealing consists in heating the piece, allowing it to...

Pyrometers
Armor plate makers sometimes use the copper ball or Siemens' ...

Silicon
Silicon prevents, to a large extent, defects such as gas bubb...

William Kelly's Air-boiling Process
An account of Bessemer's address to the British Association w...

Heat Treatment Of Punches And Dies Shears Taps Etc
HEATING.--The degree to which tools of the above classes shou...

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

Quenching The Work
In some operations case-hardened work is quenched from the bo...

Temperature For Annealing
Theoretically, annealing should be accomplished at a tempera...

Hardening High-speed Steels
We will now take up the matter of hardening high-speed steels...

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

Testing And Inspection Of Heat Treatment
The hard parts of the gear must be so hard that a new mill f...



Testing And Inspection Of Heat Treatment






Category: HEAT TREATMENT OF STEEL

The hard parts of the
gear must be so hard that a new mill file does not bite in the
least. Having passed this file test at several points, the gears go
to the center-punch test. The inspector is equipped with a wooden
trough secured to the top of the bench to support the gear, a number
of center punches (made of 3/4-in. hex-steel having points sharpened
to an angle of 120 deg.) and a hammer weighing about 4 oz. With
these simple tools, supplemented by his skill, the inspector can
feel the depth and quality of the case and the condition of the
core. The gears are each tested in this way at several points on
the teeth and elsewhere, the scrap gear being also subjected to
the test. Finally, the scrap gear is securely clamped in the
straightening press shown in Fig. 57. With a 3-1/2-lb. hammer and
a suitable hollow-ended drift manipulated by one of Sandow's
understudies, teeth are broken out of the scrap gear at various
points. These give a record confirming the center-punch tests,
which, if the angle of the center punch is kept at 120 deg. and
the weight of the hammer and blow are uniform, is very accurate.

After passing the center-punch test the ends of the teeth are peened
lightly with a hammer. If they are too hard, small particles fly
off. Such gears are drawn in oil at a temperature of from 300 to
350 deg.F., depending on their hardness. Some builders prefer to have
the extreme outer ends of the teeth drawn somewhat lower than the
rest. This drawing is done on gas-heated red-hot plates, as shown
at A in Fig. 58.



Nickel steel, in addition to all the tests given to carbon steel,
is subjected to a Brinell test. For each steel, the temperature
and the period of treatment are specific. For some unknown reason,
apparently like material with like treatment will, in isolated
cases, not produce like results. It then remains for the treatment
to be repeated or modified, but the results obtained during inspection
form a valuable aid to the metallurgist in determining further
treatment.





Next: Temperature Recording And Regulation

Previous: Affinity Of Nickel Steel For Carbon



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