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Steel Making

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

Phosphorus
Phosphorus is one of the impurities in steel, and it has been...

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

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

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

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

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

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

Quenching The Work
In some operations case-hardened work is quenched from the bo...

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

Air-hardening Steels
These steels are recommended for boring, turning and planing...

Hardening
The forgings can be hardened by cooling in still air or quen...

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

Tensile Properties
Strength of a metal is usually expressed in the number of pou...

Corrosion
This steel like any other steel when distorted by cold worki...

Cyanide Bath For Tool Steels
All high-carbon tool steels are heated in a cyanide bath. Wi...

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

Compensating Leads
By the use of compensating leads, formed of the same materia...

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

Lathe And Planer Tools
TO FORGE.--Gently warm the steel to remove any chill is parti...



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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