The effect of loading angle on the behaviour of fillet welds

The fillet weld design equation in the North American standards predicts that fillet weld strength increases as the angle between the weld axis and the loading direction increases. However, because the results upon which the equation is based were from fillet welds with relatively high toughness levels, the equation may not be suitable for welds deposited by flux-cored arc welding (FCAW) using filler metals without a toughness requirement. Therefore, the effect of toughness on fillet weld strength and ductility was investigated. Tests were conducted on longitudinal and transverse fillet welds and fillet welds oriented at 45° to the loading direction. The specimens were prepared using FCAW and filler metals with and without a specified toughness. Higher toughness was found to improve fillet weld ductility and to decrease longitudinal fillet weld strength. A reliability analysis indicated that the design equation is applicable to filler metals of a wide range of toughnesses.