At gas welding heat up edges of connected pipes a flame to fusion. In the same flame rasplavljajut prisadochnuju half so that its liquid metal has filled a backlash between welded end faces of pipes. The welded seam in the form of the platen is as a result formed.
For gas welding of pipes use mainly acetylene and oxygen.
Acetylene is a gas which burns in strue oxygen, and during its burning the temperature to 3000 В° S.Kislorod itself develops does not burn, it only sustains combustion.
Acetylene receive from calcium carbide in spetsialtsyh devices - generators. oxygen for welding arrives in steel cylinders where it is under a high pressure to 150 atm. Directly for welding of pipes the oxygen high pressure is not required, therefore pressure reduce by means of a reducer attached to a cylinder.
the Basic tools gazosvarshchika - a torch and a cutting torch. A torch (fig. 67 has two nipples for joining to it of a rubber hose from an oxygen cylinder and the same hose from gazogeneratora or an acetylene cylinder.
In a torch body pass two channels on which oxygen and acetylene arrive in the mixture chamber. From here the working mix goes to a torch nozzle. The quantity of oxygen and acetylene regulate two cranes.
Gas it is sharp it is made by cutting torches . Essence of process gas are sharp consists that metal heats up to such temperature at which it burns down in strue the oxygen arriving from a cylinder. The cutting torch (fig. 67 6) differs from a torch presence at it an additional tube 1 with the crane 2 for oxygen giving to a place are sharp.
a Fig. 67. The gas-welding tool
And - a torch; - a cutting torch; in - kerosinorez Рљ-51
At oxygen rezke metals it is possible to replace acetylene with kerosene . Installation for are sharp with kerosene application consists of a welded tank in capacity of 5 l in which kerosene is under pressure to 3 atm, kerosinoreza with a hose for kerosene and oxygen from an oxygen cylinder.
On fig. 67 in it is shown kerosinorez Рљ-51, intended both for rectilinear, and for figured became sharp in the thickness to 200 mm.