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

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

Pickling The Forgings
The forgings were then pickled in a hot solution of either ni...

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

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

Calibration Of Pyrometer With Common Salt
An easy and convenient method for standardization and one whi...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

Effect Of Different Carburizing Material
[Illustrations: FIGS. 33 to 37.] Each of these different p...

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

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

Conclusions
Martien was probably never a serious contender for the honor ...

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

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

Heat Treatment Of Gear Blanks
This section is based on a paper read before the American Gea...

Typical Oil-fired Furnaces
Several types of standard oil-fired furnaces are shown herew...

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

Hardening
Steel is hardened by quenching from above the upper critical....

Take Time For Hardening
Uneven heating and poor quenching has caused loss of many ve...

Carbon-steel Forgings
Low-stressed, carbon-steel forgings include such parts as car...

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



Making Steel Balls






Category: THE FORGING OF STEEL

Steel balls are made from rods or coils according to size, stock
less than 9/16-in. comes in coils. Stock 5/8-in. and larger comes
in rods. Ball stock is designated in thousandths so that 5/8-in.
rods are known as 0.625-in. stock.

Steel for making balls of average size is made up of:

Carbon 0.95 to 1.05 per cent
Silicon 0.20 to 0.35 per cent
Manganese 0.30 to 0.45 per cent
Chromium 0.35 to 0.45 per cent
Sulphur and phosphorus not to exceed 0.025 per cent

For the larger sizes a typical analysis is:

Carbon 1.02 per cent
Silicon 0.21 per cent
Manganese 0.40 per cent
Chromium 0.65 per cent
Sulphur 0.026 per cent
Phosphorus 0.014 per cent

Balls 5/8 in. and below are formed cold on upsetting or heading
machines, the stock use is as follows:

TABLE 14.--SIZES OF STOCK FOR FORMING BALLS ON HEADER
-------------------------------------------------------
Diameter of Diameter of Diameter of Diameter of
ball, inch stock inch ball, inch stock, inch
----------------------------------------------------
1/8 0.100 5/16 0.235
5/32 0.120 3/8 0.275
3/16 0.145 7/16 0.320
7/32 0.170 1/2 0.365
1/4 0.190 9/16 0.395
9/32 0.220 5/8 0.440
-------------------------------------------------------

For larger balls the blanks are hot-forged from straight bars.
They are usually forged in multiples of four under a spring hammer
and then separated by a suitable punching or shearing die in a
press adjoining the hammer. The dimensions are:

-----------------------------------------------------------
Diameter of ball, Diameter of die, Diameter of stock,
inch inch inch
---------------------------------------------------------
3/4 0.775 0.625
7/8 0.905 0.729
1 1.035 0.823
-----------------------------------------------------------

Before hardening, the balls are annealed to relieve the stresses
of forging and grinding, this being done by passing them through a
revolving retort made of nichrome or other heat-resisting substance.
The annealing temperature is 1,300 deg.F.

The hardening temperature is from 1,425 to 1,475 deg.F. according to
size and composition of steel. Small balls, 5/16 and under, are
quenched in oil, the larger sizes in water. In some special cases
brine is used. Quenching small balls in water is too great a shock
as the small volume is cooled clear through almost instantly. The
larger balls have metal enough to cool more slowly.

Balls which are cooled in either water or brine are boiled in water
for 2 hr. to relieve internal stresses, after which the balls are
finished by dry-grinding and oil-grinding.

The ball makers have an interesting method of testing stock for
seams which do not show in the rod or wire. The Hoover Steel Ball
Company cut off pieces of rod or wire 7/16 in. long and subject
them to an end pressure of from 20,000 to 50,000 lb. A pressure
of 20,000 lb. compresses the piece to 3/16 in. and the 50,000 lb.
pressure to 3/32 in. This opens any seam which may exist but a
solid bar shows no seam.

Another method which has proved very successful is to pass the
bar or rod to be tested through a solenoid electro-magnet. With
suitable instruments it is claimed that this is an almost infallible
test as the instruments show at once when a seam or flaw is present
in the bar.





Next: The Forging Of Steel

Previous: Heat Treatment Of Axles



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