hromium 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 coo