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   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

Quality And Structure
The quality of high-speed steel is dependent to a very great ...

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

Piston Pin
The piston pin on an aviation engine must possess maximum res...

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

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

Placing Of Pyrometers
When installing a pyrometer, care should be taken that it re...

Annealing To Relieve Internal Stresses
Work quenched from a high temperature and not afterward tempe...

Carburizing Material
The simplest carburizing substance is charcoal. It is also th...

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

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

Nickel-chromium
A combination of the characteristics of nickel and the charac...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

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

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

Hardening Carbon Steel For Tools
For years the toolmaker had full sway in regard to make of st...

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

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

Placing The Thermo-couples
The following illustrations from the Taylor Instrument Compan...

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

Crankshaft
The crankshaft was the most highly stressed part of the entir...



Hardening






Category: ALLOYS AND THEIR EFFECT UPON STEEL

The forgings can be hardened by cooling in still air
or quenching in oil or water from a temperature between 1,650 and
1,750 deg.F.

The physical properties do not vary greatly when the carbon is
within the range of composition given, or when the steel is hardened
and tempered in air, oil, or water.

When used for valves the following specification of physical properties
have been used:

Yield point, pounds per square inch 70,000
Tensile strength, pounds per square inch 90,000
Elongation in 2 in., per cent 18
Reduction of area, per cent 50

The usual heat treatment is to quench in oil from 1,650 deg.F. and
temper or draw at 1,100 to 1,200 deg.F. One valve manufacturer stated
that valves of this steel are hardened by heating the previously
annealed valves to 1,650 deg.F. and cooling in still air. This treatment
gives a scleroscope hardness of about 50.

In addition to use in valves this steel should prove very satisfactory
for shafting for water-pumps and other automobile parts subject to
objectionable corrosion.

TABLE 2.--COMPARISON OF PHYSICAL PROPERTIES FOR HIGH-CHROMIUM
STEELS OF DIFFERENT CARBON CONTENT --------------------------------------------------------------------------
C 0.20 C 0.27 C 0.50
Mn 0.45 Mn 0.50
Cr 12.56 Cr 12.24 Cr 14.84
-----------------------------------------------------------------------
Quenched in oil from degrees Fahrenheit 1,600 1,600 1,650
Tempered at degrees Fahrenheit 1,160 1,080 1,100
Yield point, pounds per square inch 78,300 75,000 91,616
Tensile strength, pounds per square inch 104,600 104,250 123,648
Elongation in 2 in., per cent 25.0 23.5 14.5
Reduction of area, per cent 52.5 51.4 33.5
--------------------------------------------------------------------------

TABLE 3.--COMPARISON OF PHYSICAL PROPERTIES BETWEEN AIR, OIL AND
WATER-HARDENED STEEL HAVING CHEMICAL ANALYSIS IN
PERCENTAGE OF
-------------------------------------------------------------------------
Carbon 0.24
Manganese 0.30
Phosphorus 0.035
Sulphur 0.035
Chromium 12.85
Silicon 0.20

-------------------------------------------------------------------------
Hardened Elastic Tensile
Hardening from, Tempered limit, strength,ElongationReduction
medium degrees at, degrees per lb. lb. Per in 2 in. of area,
FahrenheitFahrenheit sq. in. sq. in. per cent per cent
-------------------------------------------------------------------
930 158,815 192,415 13.0 40.5
1,100 99,680 120,065 21.0 59.2
Air 1,650 1,300 70,785 101,250 26.0 64.6
1,380 66,080 98,335 28.0 63.6
1,470 70,785 96,990 27.0 64.7
-------------------------------------------------------------------
930 163,070 202,720 8.0 18.2
Oil 1,650 1,100 88,255 116,480 20.0 56.9
1,300 77,950 105,505 25.5 63.8
1,380 88,255 98,785 27.0 66.3
-------------------------------------------------------------------
930 158,815 202,050 12.0 34.2
Water 1,650 1,100 90,270 120,735 22.0 59.8
1,300 66,080 102,590 25.8 64.8
1,380 67,200 97,890 27.0 65.2
-------------------------------------------------------------------------

This steel can be drawn into wire, rolled into sheets and strips
and drawn into seamless tubes.





Next: Corrosion

Previous: Annealing



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