As soon as the metal reaches this temperature, the high
pressure oxygen is turned on to the white-hot portion of the steel. When
the jet of gas strikes the metal it cuts straight through, leaving a very
narrow slot and removing but little metal. Thicknesses of steel up to ten
inches can be economically handled in this way.
The oxygen nozzle is usually arranged so that it is surrounded by a number
of small jets for the heating flame. It will be seen that this arrangement
makes the heating flame always precede the oxygen jet, no matter in which
direction the torch is moved.
The torch is held firmly, either by hand or with the help of special
mechanism for guiding it in the desired path, and is steadily advanced in
the direction it is desired to extend the cut, the rate of advance being
from three inches to two feet per minute through metal from nine inches
down to one-quarter of an inch in thickness.
The following data on cutting is given by the Davis-Bournonville Company:
Cubic
Feet Cost of
Thickness of Gas Inches Gases
of Cutting Heating per Foot Oxygen Cut per per Foot
Steel Oxygen Oxygen of Cut Acetylene Min. of Cut
1/4 10 lbs. 4 lbs. .40 .086 24 $ .013
1/2 20 4 .91 .150 15 .
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