This technique (autogenous (lat.) = self working) means working with materials or heating of workpieces by means of a flame. The term “Autogenous Technique” includes different processes, where the process heat is generated by a flame.
Important Flame Processes
The heat source is a chemical reaction resulting from the combustion of the fuel gas with oxygen. This is an exothermic reaction.
Flame straightening is an efficient method of correcting distorted parts.
It is based on the physical principle that metals expand when heated and contract when cooled. If expansion is limited, compressive stresses built up and result in plastic deformations. Upon cooling, the plastic deformations remain, and they shorten the heated area.
The term “flame heating” refers to processes in which heat is transferred to the workpiece by means of a flame without the workpiece melting or material being removed. There are a lot of different processes.
Flame Spraying. The flame heating process is used for machining of the workpiece surface. The surfaces of steel and concrete, for example, can be cleaned or prepared for the following coating.
Concrete and rocks can, for optical or adhesion improvement effects, also be surface roughened.
Thermal Cutting of e.g. concrete. The oxygen-lance cutting with the oxygen lance is a thermal hole piercing.
The oxygen lance burns off with the oxygen inflow, the reaction heat enables to deposit steel or concrete as well as rocks.
When Oxy-Acetylene Welding a weld pool is created by immediate, locally restricted influence of an oxygen-fuel or an air-fuel flame.
The advantages of Oxy-Acetylene Welding are as follows:
-low investment costs
-variable use of the equipment
-good to use in out-of-position welding.
Soldering and Brazing. When soldering a solder filling metal with a lower melting point than the one of the base material is deposited with a flame. By wetting of the metal surfaces a joint between the workpiece is achieved.
When autogenous Oxy-Fuel-Cutting the working material is oxidised by the oxygen jet.
The resulting heat enables continuous cutting. The oxide products are pushed out of the kerf by the oxygen jet. For this reason also extremely thick workpieces can be cut.