: The Working Of Steel

Molybdenum steels have been made commercially for twenty-five years,

but they have not been widely exploited until since the war. Very

large resources of molybdenum have been developed in America, and

the mining companies who are equipped to produce the metal are

very active in advertising the advantages of molybdenum steels.

It was early found that 1 part molybdenum was the equivalent of from

2 to 2-1/2
arts of tungsten in tool steels, and magnet steels. It

fell into disrepute as an alloy for high-speed tool steel, however,

because it was found that the molybdenum was driven out of the

surface of the tool during forging and heat treating.

Within the last few years it has been found that the presence of

less than 1 per cent of molybdenum greatly enhances certain properties

of heat-treated carbon and alloy steels used for automobiles and

high-grade machinery.

In general, molybdenum when added to an alloy steel, increases the

figure for reduction of area, which is considered a good measure

of toughness. Molybdenum steels are also relatively insensible

to variations in heat treatment; that is to say, a

chromium-nickel-molybdenum steel after quenching in oil from 1,450 deg.F.

may be drawn at any temperature between 900 and 1,100 deg.F. with

substantially the same result (static tensile properties and hardness).