Butts

In this paper, 2D simulations of the ultrasonic testing of different types of (transversely isotropic) austenitic V-butt welds are presented they have been obtained with an EFIT-code developed by Marklein [5]. 

The austenitic and, hence, anisotropic V-butt weld is embedded in isotropic steel it has a width of 10 mm at its baseline and a height of 30 mm. If a notch is present, it has a width of 1 mm and a height of 15 mm it is located at the right-hand side of the V-butt weld. The simulated transducer is a commercial 45°-shear wave probe (MWB45-2E). The parameters varied during the simulations are ... 

Simulations of that kind result in a wide variety of A-scans and wavefront snapshots. The first screening of this material reveals, that the simulations in which the transducer is coupling partly to the V-butt weld and partly to the steel exhibit quite a number of pulses in the A-scans because the coupling at the interface of the weld results — due to the anisotropic behavior of the weld — in a complicated splitting of the transmitted wavefront. The different parts of the splitted wavefront are reflected and diffracted by the backwall, the interface, and — if present — by the notch and, therefore, many small signals are received by the transducer, which can only be separated and interpreted with great difficultie.s. 

Only the simulations in which the transducer is coupling either to the V-butt weld or to the surrounding steel can be analyzed in a simple and intuitive way, which means that the different pulses in the A-scan signals can be related uniquely to the reflection or diffraction of the wavefront at the weld, the backwall, and/or the notch. 

Second corner reflection The first corner reflection appears as usual when the transducer is coupled to the probe at a certain distance from the V-butt weld. The second corner reflection appears if the transducer is positioned well above the V-hutt weld. If the weld is made of isotropic material the wavefront will miss (pass) the notch without causing any reflection or diffraction (see Fig. 3(a)) for this particular transducer position. In the anisotropic case, the direction of the phase velocity vector will differ from the 45° direction in the isotropic case. Moreover, the direction of the group velocity vector will no longer be the same as the direction of the phase velocity vector (see Fig. 3(b), 3(c)). This can be explained by comparing the corresponding slowness and group velocity diagrams. 

Figure 7 V-butt weld with perpendicular grain orientation and an inclination of the interface of 15° left without, right with backwall breaking notch...

In order to solve the problem of detect control of axial canal without preliminary surface clearing, the eddy-current transformer with operating butt end... 

Intersections of butts and seams of fabrication and section welds Throughout hull envelope, longitudinal and transverse bulkheads, inner bottom and hopper bottom The summation of checkpoint lengths (see note 2) examined at intersections is to be L where L is the overall length of the ship in metres... 

Butts in longitudinals Hull envelope within 0.4L amidships Hull envelope outside 0.4L amidships 1 in 10 welds (see note 5) 1 in 20 welds... 

Morse T 1979 Handbook of Organic Additives for Use in Ceramic Body Formuiation (Butte, MA Montana Energy and MHD Research and Deveiopment institute)... 

It appears that a loose interpretation of this type may be the origin of a discrenancy found by Otanl and Smith [59] in attempting to apply effective diffusivities from Wakao and Smith s [32] isobaric diffusion data to measurements on a chemically reacting system. This was pointed out by Steisel and Butt [60], and further pursued to the point of detailed computer modeling of a particular pore network by Wakao and Nardse [61]. 

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