ESAB Knowledge center.
Welding Flux Basicity Index
Basicity is commonly used to describe the metallurgical behavior of a welding flux. The basicity index is a ratio between basic and acid compounds (oxides and fluorides) of which the flux is composed.
There are several ways of calculating basicity and in welding Boniszewski's formula has become the predominant way of calculating basicity.
Welding fluxes can be divided into three groups:
|Type of welding flux||Basicity|
|Neutral fluxes||0.9 - 1.2|
The relation between basicity and impact toughness is particularly important for high alloyed grades, such as duplex steels.