DILUTION IN SINGLE-PASS ARC WELDS

A study was conducted on dilution of single pass are welds of type 308 stainless steel filler metal deposited onto A36 carbon steel by the p lasma are welding (PAW), gas tungsten are welding (GTAW), gas metal ar e welding (GMAW), and submerged are welding (SAW) processes. Knowledge of the are and melting efficiency was used in a simple energy balance to develop an expression for dilution as a function of welding variab les and thermophysical properties of the filler metal and substrate. C omparison of calculated and experimentally determined dilution values shows the approach provides reasonable predictions of dilution when th e melting efficiency can be accurately predicted. The conditions under which such accuracy is obtained are discussed. A diagram is developed from the dilution equation which readily reveals the effect of proces sing parameters on dilution to aid in parameter optimization.