Autogenous preheat flame coefficient
The autogenous preheat flame coefficient describes the energy ratio between fuel gas and oxygen in the primary flame of the oxy-fuel torch. It ensures that the ignition temperature is reached on the plate surface.
Physicochemical mechanism of action
The autogenous preheat flame coefficient is a measure of the energy ratio between fuel gas and oxygen in the primary flame of the oxy-fuel torch. This coefficient determines the ignition temperature necessary to start the combustion.
Metallurgical relevance & risks in welding
An insufficient preheat flame coefficient can lead to inadequate preheating of the plate surface. This can result in incomplete combustion and a sluggish burning process, which in turn leads to porosity and low strength of the weld. Conversely, a too high coefficient can cause overheated flames that may damage the metal.
Workshop practice & instructions
To set the autogenous preheat flame coefficient correctly, the oxygen supply must be precisely controlled. A typical coefficient is about 1.25 to 1.30. For a too low coefficient (below 1.20), increase the oxygen supply, while a too high coefficient (above 1.40) requires reducing the oxygen supply. The exact setting depends on the metals used and the specific welding process.