ith ferrite. If vanadium contained is considerable it also combines
with the carbon, forming carbides. The ductility of carbon-vanadium
steels is therefore increased, likewise the ductility of chrome-vanadium
steels.

The full effect of vanadium is not felt unless the temperatures to
which the steel is heated for hardening are raised considerably.
It is therefore necessary that a certain amount of "soaking" takes
place, so as to get the necessary equalization. This is true of all
alloys which contain complex carbides, i.e., compounds of carbon,
iron and one or more elements.

Chrome-vanadium steels also are highly favored for case hardening.
When used under alternating stresses it appears to have superior
endurance. It would appear that the intensification of the properties
due to chromium and manganese in the alloy steel accounts for this
peculiar phenomenon.

Vanadium is also a very excellent scavenger for either removing
the harmful gases, or causing them to enter into solution with the
metal in such a way as to largely obviate their harmful effects.
Chrome-vanadium steels have been claimed, by many steel manufacturers
and users, to be preferable to nickel-chrome steels. While not
wishing to pass judgment on this, it should be borne in mind that
the chrome-vanadium steel, which is tested, is generally compared
with a very low nickel-chromium alloy steel (the price factor entering
into the situation), but equally good results can be obtained by
nickel-chromium steels of suitable analysis.

Where price is the leading factor, there are many cases where a
stronger steel can be obtained from the chrome and vanadium than
the nickel-chrome. It will be safe to say that each of these two
systems of alloys have their own particular fields and chrome-vanadium
steel should not be regarded as the sole solution for all problems,
neither should nickel-chromium.

MANGANESE

Manganese adds considerably to the tensile strength of steel, but
this is dependent on the carbon content. High carbon materially adds
to the brittleness, whereas low-carbon, pearlitic-manganese steels
are very tough and ductile and are not at all brittle, providing the
heat-treating is correct. Manganese steel is very susceptible to
high temperatures and prolonged heating.

In low-carbon pearlitic steels, manganese is more effective in
increasing ultimate strength than is nickel; that is to say, a
0.45 carbon steel with 1.25 per cent manganese is as st