TWI Industrial Member Report Summary 75/1976
By F R Coe
The literature dealing with the physical and chemical properties of fluxes and slags in arc welding is critically reviewed. Values for low temperature properties such as grain size, bulk density, flowability and hygroscopicity are discussed and high temperature properties such as melting range, thermal behaviour, coefficient of expansion, liquid density, viscosity, surface tension and electrical conductivity are examined for the various chemical compositions occurring.
The nature and structure of complex melts is examined and the concept of basicity reviewed. Slag-metal reactions occurring during the short contact times of welding are examined for some of the major elements in an attempt to discover whether classical reaction thermodynamics are capable of predicting how flux and slag composition governs weld metal composition.