Fatigue Failure Caused by Weld Spatter

A medium-carbon helical spring was installed in a machine assembly that was welded into its final location. Weld spatter was not prevented from landing on the wire surface by any shield. An elongated drop and two tiny droplets of metal were observed a short distance from the fracture. No droplets were revealed at the origin of the fracture, but it was assumed that a drop of molten metal landed at the origin. Adherence of the spatter drop was expected to have been affected by the opening and closing of the fatigue crack. Weld spatter bead was concluded to have caused the fatigue fracture.