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Steel Making

Composition And Properties Of Steel
It is a remarkable fact that one can look through a dozen tex...

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

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

Forging High-speed Steel
Heat very slowly and carefully to from 1,800 to 2,000 deg.F....

Heating Of Manganese Steel
Another form of heat-treating furnace is that which is used ...

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

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

Carbon In Tool Steel
Carbon tool steel, or tool steel as it is commonly called, us...

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

High Speed Steel
For centuries the secret art of making tool steel was handed ...

Classifications Of Steel
Among makers and sellers, carbon tool-steels are classed by g...

Reheating for machine ability was done at 100 deg. less than ...

The Packing Department
In Fig. 56 is shown the packing pots where the work is packe...

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

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

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

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

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

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

Making Steel Balls


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:

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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