Abstract
Gusset welded joint is known as having the lowest fatigue strength among other types of welded joints. In order to improve the fatigue strength of gusset welded joints, the effect of the shape of weld ends on fatigue strength was investigated for three types of gusset welded joints using mild steel (SS41). Non-load carrying and load carrying gusset welded joints were examined, which were boxing fillet welding (type A and A'), side fillet welding (type B and B') and lengthened side fillet welding (type C and C') types.
The test result indicates that the fatigue strength increases in the following order, type A and A'<type B and B'<type C and C' and that type C and C' are about 22% stronger than type A and A' at N=2×106. This result can be discussed in terms of difference in notch effect at the weld ends and in crack propagation process. The effect of residual stress may be insignificant.
The effect of toe grinding was also investigated. Toe grinding increased fatigue strength of type A' and did not increase that of type C' while it changed location and appearance of the fracture.
