The influence of weld joint integrity on Fatigue properties in carbon steel

Abstract

Present research is mainly studying the influence of formation weld inclusions on the fatigue life to failure using mild steel compact tension specimen of 6mm thickness with weld position normal to the notch tip where crack is supposed to initiate and propagate toward the weld line which is about 3-to 5 mm away from the notch. The weld was conducted using shield metal arc welding method while the filler weld type used is E6010 Fatigue tests for all the prepared specimens were implemented under a constant load amplitude of 6 KN with loading frequency around 80 HZ, Different numbers of stress ratio were used during tests as explained later on. All tests give a confirmed results that fatigue life improved as stress ratio decreased while the number of fatigue cycle to failure were suddenly decrease when the crack tip hit the spherical weld inclusion which is considered as harmful defect on the weld joint. Scanning electron machine was massively used to investigate the fractur surfaces features and to show the shape and position of the inclusions.