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Steel Making

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

Carburizing By Gas
The process of carburizing by gas, briefly mentioned on page ...

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...

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

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

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

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

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

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Connecting Rods
The material used for all connecting rods on the Liberty engi...

Alloying Elements
Commercial steels of even the simplest types are therefore p...

Non-shrinking Oil-hardening Steels
Certain steels have a very low rate of expansion and contract...

Cutting-off Steel From Bar
To cut a piece from an annealed bar, cut off with a hack saw,...

Rate Of Cooling
At the option of the manufacturer, the above treatment of gea...

The Penetration Of Carbon
Carburized mild steel is used to a great extent in the manufa...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

Plant For Forging Rifle Barrels
The forging of rifle barrels in large quantities and heat-tre...

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

Sulphur
SULPHUR is another element (symbol S) which is always found i...

Composition Of Transmission-gear Steel
If the nickel content of this steel is eliminated, and the pe...



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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