Dynamical Characteristics of Weld Cracking in Multipass Welded Corner Joint

Abstract

Lamellar tearing of opening type and root cracking occasionally occur in multipass welded corner joints.
In this paper, a relation between the occurrence of these weld cracks and the intensity of bending restraint is examined with the aid of the CJC-test. Furthermore, welding residual stresses in corner joints are analyzed and measured. Dynamical conditions for the occurrence of these weld cracks are investigated.
The summary of the results obtained from this study are as follows.
(1) In the case where the intensity of bending restraint is large: The lamellar tearing of opening type occurs at the position about 10 mm away from the toe, but root cracking does not occur. Large tensile welding residual stresses are induced on the edge surface of the vertical plate at the position about 10 mm away from the toe, but large compressive stresses are induced near the root.
(2) In the case where the intensity of bending restraint is small: The lamellar tearing does not occur but root cracking occurs. Tensile stresses on the edge surface are less than those in the case of the intensity of bending restraint being large, but very large tensile stresses are induced near the root. Accordingly, the tendency of the occurrence of weld cracking in multipass welded corner joints is closely related to welding residual stress distribution, and can be explained well from the dynamical point of view.