Page 32 - CITS - Welder - Trade Theory

WELDER - CITS

Too much preheating. The cut shows a rounded top edge caused by too much preheat. Excess preheating does
not increase the cutting speed, it only wastes gases. (Fig 5)

Fig 5

Poor quality bevel cut. The most common fault is gouging, caused by either excessive speed or inadequate
preheat flames. Another fault is a rounded top edge caused by too much preheat, indicating excessive gas
consumption. (Fig 6)
Fig 6

Slightly too fast a cutting speed. The drag lines on this cut incline backwards, but a drop cut’ is still attained.
The top edge is good; the cut face is smooth and slag-free. This quality is satisfactory for most production work.
(Fig 7)

Fig 7

Slightly too slow a cutting speed. The cut is of high quality although there is some surface roughness caused
by the vertical drag line. The top edge is usually slightly beaded. This quality is generally acceptable, but faster
speeds are more desirable because the labour cost for this cut is too high. (Fig 8)

Fig 8

In a good cut, the edges are square, and the lines of cut are vertical. (Fig 9)

Fig 9

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