Английский для сварщиков. Гричин С.В. - 85 стр.

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or by some other means. After the flame is adjusted to the proper size, open

the oxygen valve and adjust it to give the desired balance of fuel and oxygen.

Usually a neutral flame is used: this is a flame where the fuel and oxygen

supplied to the torch tip are both completely combined with each other. An

oxidizing flame has an excess of oxygen and a reducing flame has an excess

of fuel (carbon). An oxidising flame is used for cutting and a reducing flame

is used for annealing e.g. to soften steel sheet metal.

An acetylene flame (as is characteristic of most fuel/oxygen flames)

has two parts; the light blue to white colored inner cone and the blue colored

outer cone. The inner cone is where the acetylene and the oxygen combine.

The tip of this inner cone is the hottest part of the flame. The outer cone is

where hydrogen and carbon monoxide from the breakdown of the acetylene

and partial combustion of the inner cone combine with the oxygen in the

surrounding air and burns.

A neutral flame has a well defined inner cone. A reducing flame has a

feathery inner cone. An oxidizing flame has a smaller inner cone that is

sharply defined and is pale blue. The welder observes this while adjusting the

fuel and oxygen valves on the torch to get the correct balance for the job at

hand. There is also a difference in the noise the flame makes. Adjusting the

flame is not a hard thing to do after a little experience and practice.

The size of the flame can be adjusted to a limited extent by the valves

on the torch and by the regulator settings, but in the main it depends on the

size of the orifice in the tip. In fact, the tip should be chosen first according to

the job at hand, and then the regulators set accordingly.

The flame is applied to the base metal and held until a small puddle of

molten metal is formed. The puddle is moved along the path where the weld

bead is desired. Usually, more metal is added to the puddle as it is moved

along by means of dripping metal from a wire ("welding rod" or "filler rod")

into the molten metal puddle. The force of the jet of flame issuing from the

torch tip helps to manipulate the puddle. The amount of heat can be

controlled by the distance of the flame from the metal. There should be a

bright, incandescent spot on the molten puddle. When the puddle is correctly

maintained, a sound weld will result.