Given that the overall expansivity is almost the same for all three materials (see Table 12.12) the differences in angular distortion would seem to be related to the fact that the phase change expansion for the low-transformation-start material is occurring in a cooling regime where it is developing greater yield strength. A similar pattern is seen in the solutions where actual welding parameters were applied, when due allowance is made for the differences in heat input. The results for distortion range reflect the angular distortions at the finish end. Angular distortion is increased, however. In the cases where identical welding parameters and heat inputs were applied, longitudinal bowing is reduced when low-transformation-start filler (LT) is used, by a small but identifiable amount. The differences in predicted distortion between the three filler materials are relatively small. We will give, without proof, the formulas for calculation of stresses σ x, σ y and τ xy, when measurements are taken using three gauges. In the case of stress measurement at the plate edges two gauges will not be enough, and a full rosette of three gauges is required. A rectangular rosette of two gauges was glued on at each point of stress measurement.
Gauges were glued to the plate surface, using glue of Tsiakrin grade. Stresses σ y contrarily, become smaller in magnitude with the increase of distance x from the plate edge.īoth in the case of butt welding of a plate, and in welding of stiffeners to it, strain gauges with 5 mm base and electric resistance of 90 Ohm were used for stress measurement. It is interesting to note in both experiments a confirmation of the earlier derived theoretical results on stresses σ x being equal to zero on the plate front edges, their increase with distance x and achievement of the maximal value at x = 20 cm and more. Stresses were measured in the sections of the plate and the stiffeners along the weld line at different distances x from the front edge (shown in the graph).
0 kommentar(er)
