Carburizing By Gas

: The Working Of Steel

The process of carburizing by gas, briefly mentioned on page 88,

consists of having a slowly revolving, properly heated, cylindrical

retort into which illuminating gas (a mixture of various hydrocarbons)

is continuously injected under pressure. The spent gases are vented

to insure the greatest speed in carbonizing. The work is constantly

and uniformly exposed to a clean carbonizing atmosphere instead

of partially spent carbonaceous solids which may give off very

complex compounds of phosphorus, sulphur, carbon and nitrogen.

Originally this process was thought to require a gas generator but

it has been discovered that city gas works all right. The gas consists

of vapors derived from petroleum or bituminous coal. Sometimes the

gas supply is diluted by air, to reduce the speed of carburization

and increase the depth.