0.36 | 0.50 | 1.30 | 0.75 | 0.16 |140,000| 157,500 | 17 | 54
0.30 | 0.50 | | 0.80 | | 90,000| 105,000 | 20 | 50
0.23 | 0.58 | | 0.82 | 0.17 |106,000| 124,000 | 21 | 66
0.26 | 0.48 | | 0.92 | 0.20 |112,000| 137,000 | 20 | 61
0.35 | 0.64 | | 1.03 | 0.22 |132,500| 149,500 | 16 | 54
0.50 | 0.92 | | 1.02 | 0.20 |170,000| 186,000 | 15 | 45
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NON-SHRINKING, OIL-HARDENING STEELS

Certain steels have a very low rate of expansion and contraction
in hardening and are very desirable for test plugs, gages, punches
and dies, for milling cutters, taps, reamers, hard steel bushings
and similar work.

It is recommended that for forging these steels it be heated slowly
and uniformly to a bright red, but not in a direct flame or blast.
Harden at a dull red heat, about 1,300 deg.F. A clean coal or coke
fire, or a good muffle-gas furnace will give best results. Fish
oil is good for quenching although in some cases warm water will
give excellent results. The steel should be kept moving in the bath
until perfectly cold. Heated and cooled in this way the steel is
very tough, takes a good cutting edge and has very little expansion
or contraction which makes it desirable for long taps where the
accuracy of lead is important.

The composition of these steels is as follows:

Per cent
Manganese 1.40 to 1.60
Carbon 0.80 to 0.90
Vanadium 0.20 to 0.25

[Illustration: FIG. 13.--Effect of copper in steel.]

EFFECT OF A SMALL AMOUNT OF COPPER IN MEDIUM-CARBON STEEL

This shows the result of tests by C. R. Hayward and A. B. Johnston
on two types of steel: one containing 0.30 per cent carbon, 0.012
per cent phosphorus, and 0.860 per cent copper, and the other 0.365
per cent carbon, 0.053 per cent phosphorus, and 0.030 per cent
copper. The accompanying chart in Fig. 13 shows that high-copper
steel has decided superiority in tensile strength, yield point and
ultimate strength, while the ductility is practically the same.
Hardness tests by both methods show high-copper steel to be harder
than low-copper, and the Charpy shock tests show high-copper steel
also superior to low-copper. The tests confirm those made by Stead,
showing that the behavior of copper steel resembles that of nickel
steel. The high-copper steels show finer g