スリット溶接継手に生じる拘束応力・拘束ひずみの一般特性及び拘束度の力学的指標としての意義

抄録

The mechanism of the cold weld cracking may be simply stated from the mechanical aspect that the cold crack initiates when the stress and strain induced at a point reach the critical values. In this respect, the stress and strain are the important information to prevent initiation of cold cracking from the dynamical point of view. In connection to this, a series of researches is carried out on this kind of problems. A slit weld in a rectangular plate is chosen as the basic research model because of its two dimensional restraint state in which the constraint of thermal expansion and shrinkage varies along the weld line.
In this paper, experiments are conducted in order to investigate the validity of the already proposed analytical calculation method for the inherent shrinkage which is the direct factor of producing restraint stresses and strains in the perpendicular direction to the weld line and for thus produced restraint stresses and strains. From the result, the characteristics of the restraint stress and strain produced in the weld metal are clarified. At the same time, the restraint strain which can be estimated by a simple calculation is proposed as a more general dynamical measure for initiation of cold cracking. In addition, the restraint intensities under three loading conditions are investigated of their significance as a dynamical factor in case of estimating the restraint stress and strain.