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Steel Making

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

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

Complete Calibration Of Pyrometers
For the complete calibration of a thermo-couple of unknown e...

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

The Influence Of Size
The size of the piece influences the physical properties obta...

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

Affinity Of Nickel Steel For Carbon
The carbon- and nickel-steel gears are carburized separately...

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

Knowing What Takes Place
How are we to know if we have given a piece of steel the ver...

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

Although it is possible to work steels cold, to an extent de...

Tungsten, as an alloy in steel, has been known and used for a...

Detrimental Elements
Sulphur and phosphorus are two elements known to be detrimen...

Properties Of Steel
Steels are known by certain tests. Early tests were more or l...

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...

Preparing Parts For Local Case-hardening
At the works of the Dayton Engineering Laboratories Company, ...

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

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

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

The Quenching Tank
The quenching tank is an important feature of apparatus in c...

Testing And Inspection Of Heat Treatment


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

Next: Temperature Recording And Regulation

Previous: Affinity Of Nickel Steel For Carbon

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