VIEW THE MOBILE VERSION of Informational Site Network Informational
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Hardness Testing
The word hardness is used to express various properties of me...

The Care Of Carburizing Compounds
Of all the opportunities for practicing economy in the heat-t...

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

Oil-hardening Steel
Heat slowly and uniformly to 1,450 deg.F. and forge thorough...

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

ANNEALING can be done by heating to temperatures ranging from...

There is no mystery or secret about the proper annealing of d...

Fatigue Tests
It has been known for fifty years that a beam or rod would fa...

Annealing Of Rifle Components At Springfield Armory
In general, all forgings of the components of the arms manufa...

The Modern Hardening Room
A hardening room of today means a very different place from ...

The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely nece...

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

The Theory Of Tempering
Steel that has been hardened is generally harder and more br...

Care In Annealing
Not only will benefits in machining be found by careful anne...

A Satisfactory Luting Mixture
A mixture of fireclay and sand will be found very satisfactor...

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

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

Steel Can Be Worked Cold
As noted above, steel can be worked cold, as in the case of ...

Brown Automatic Signaling Pyrometer
In large heat-treating plants it has been customary to mainta...

Standard Analysis
The selection of a standard analysis by the manufacturer is t...

Complete Calibration Of Pyrometers


For the complete calibration
of a thermo-couple of unknown electromotive force, the new couple
may be checked against a standard instrument, placing the two bare
couples side by side in a suitable tube and taking frequent readings
over the range of temperatures desired.

If only one instrument, such as a millivoltmeter, is available,
and there is no standard couple at hand, the new couple may be
calibrated over a wide range of temperatures by the use of the following

Water, boiling point 212 deg.F.
Tin, under charcoal, freezing point 450 deg.F.
Lead, under charcoal, freezing point 621 deg.F.
Zinc, under charcoal, freezing point 786 deg.F.
Sulphur, boiling point 832 deg.F.
Aluminum, under charcoal, freezing point 1,216 deg.F.
Sodium chloride (salt), freezing point 1,474 deg.F.
Potassium sulphate, freezing point 1,958 deg.F.

A good practice is to make one pyrometer a standard; calibrate it
frequently by the melting-point-of-salt method, and each morning
check up every pyrometer in the works with the standard, making the
necessary corrections to be used for the day's work. By pursuing
this course systematically, the improved quality of the product
will much more than compensate for the extra work.

The purity of the substance affects its freezing or melting point.
The melting point of common salt is given in one widely used handbook
at 1,421 deg.F., although chemically pure sodium chloride melts at
1,474 deg.F. as shown above. A sufficient quantity for an extended
period should be secured. Test the melting point with a pyrometer
of known accuracy. Knowing this temperature it will be easy to
calibrate other pyrometers.

Next: Placing Of Pyrometers

Previous: Calibration Of Pyrometer With Common Salt

Add to Add to Reddit Add to Digg Add to Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network

Viewed 3378