TWI Industrial Member Report Summary 38/1977
By N Bailey and M L E Davis
The first part of this survey dealt with the role of welding fluxes, their manufacture and their physical properties and associated weldability. The second part considered the effects of flux on weld properties and defects. This final part considers the classification of fluxes and then summarises the complete survey highlighting gaps in the knowledge and discussing problem areas where further work is needed.
Whilst the idea of a simple numerical classification system is attractive, the applicability of the present systems to all fluxes would be too complex for everyday use. A simple system based on the compositional type is suggested for the present time, although a better understanding of flux chemistry, the subject of a companion report, is likely to allow rational classification systems to be developed.
In the overall summary it is concluded that sufficient is known to enable scientific investigations to be carried out in several important areas. These included work to enable weld compositions to be predicted from flux compositions, major investigations into weld strength and toughness and less comprehensive ones on fatigue and creep behaviour.
The major problem of understanding how fluxes affect welding behaviour can best be studied by examining how flux physical properties affect welding behaviour and how these properties are, in turn, controlled by the flux composition. Such an understanding should lead to a rational basis for improving fluxes, their quality control and how to select and use them.