Page 31 - CITS - Welder - Trade Theory

WELDER - CITS

Fig 1

Extremely slow cutting speed. Pressure marks on the cut face indicate too much oxygen for the cutting conditions.
Either the tip is too big, the cutting oxygen pressure is too high, or the speed is too slow as shown by the rounded
or beaded top edge. On reducing the cutting oxygen volume to the correct proportions for the thickness of the cut,
the pressure marks will recede toward the bottom edge until they finally disappear. (Fig 2)

Fig 2

Tip too close to the steel. The cut shows grooves and deep drag lines, caused an unstable cutting action. Part of
the preheat cones burned inside the kerf, where normal gas expansion affected the oxygen cutting stream. (Fig 3)

Fig 3

Too much cutting oxygen. The cut shows pressure marks caused by too much cutting oxygen. When more oxygen
is supplied than can be consumed in oxidation, the remainder flow around the slags, creating gouges or pressure
marks. (Fig 4)

Fig 4

18

CITS : C G & M - Welder - Lesson 4&5