Parallel plate welding

Short glass fibers are commonly added to polymers to enhance their properties. When joining these materials, it is desirable to maintain the enhanced characteristics of the bulk material at the weld interface by orienting the fibers perpendicular to, and across the joint. However, in most conventional plastics welding processes, such as hot plate welding, the glass fibers tend to orient themselves parallel to the weld joint. 

Special contact transducers having wedges providing incidence angles for specific appHcations are used widely in industry. For example, normal incidence is used in tests for laminations within sheets, and for sheet or plate thickness where the back surface of the test material parallels, to within perhaps 10°, the front surface. Shear wave transducers typically used for weld examination have 45°, 60°, or 70° inspection (refracted) angles. To locate discontinuities, the transducers may be moved back and forth over selected surface areas until the angled search beam approaches normal incidence on the... 

Change in section at weld bead. Gives stress concentration. In the case of butt welds this can be removed by grinding back the weld until flush with the parent plates. Grinding marks must be parallel to loading direction otherwise they can initiate fatigue cracks. 

Microfabrication of the parallel channels was performed by mechanical surface cutting of metal tapes [31]. In the case of aluminum alloys, ground-in monocrystalline diamonds were used [45]. In the case of iron alloys, ceramic micro tools have to be used owing to the incompatibility of diamonds with that material. Such a microstructured platelet stack is provided with top and cover plates, diffusion bonded and connected to suitable fittings for the inlet and withdrawal ducts by electron beam welding (Figure 3.9). 

The development of explosive cladding is very much more advanced the metal sheet to be cladded is exploded onto the base material, parallel to it or at a certain angle. In this way it is possible to effect cladding tasks which would be impossible to fulfil by manual welding, owing to the formation of brittle intermediate alloys between the plating material and the base material - as, for instance, in plating titanium onto a steel surface. 

About 1948, hollow plates of stamped and welded steel were introduced. While these reduced costs, it was difficult to achieve completely flat and parallel faces and plates which would not become deformed. These problems have not yet been solved satisfactorily, and this innovation cannot be considered successful because of more frequent dielectric breakage. 

Residual stresses induced by variable polarity plasma arc (VPPA) welding in an A1 alloy 2219-T851 plate (6.5 mm thickness - Z direction, 62 mm in the direction parallel to the weld axis - Y direction, 48 mm in the direction perpendicular to it - X direction) were investigated by neutron diffraction [5], Measurements were performed by neutron diffraction, using the time of flight (TOF) technique, with a 2x10x2 mm3 sampling volume. 

The velocity of the fluid inside the tubes is a function of the number of tubes in parallel. To reduce the number of tubes in parallel, partition plates are used. For example, in the exchanger shown in Figure 2-3 cooling water flows through only half the tubes in parallel. Dividing the total number of tubes into two halves is accomplished very simply by welding a flat horizontal partition plate in the middle of the channel. 

Fig. 5.10 Crack growth data in 2024-T351 for cracks grow-ing parallel to the weld in compact tension samples and cracks located at various distances from the plate joint line (PJL). Source Ref 1 2...

The specimens were cut from the plate in two directions longitudinal and transverse to the rolling direction. The welded joint specimens were cut transverse to the weld. The notch in the welded joint specimens was made in the plane parallel to the weld direction. Tests were conducted at room temperature and at 77 K. The topographical features of the fracture surfaces of notched specimens were revealed by the fractographic method and with a scanning electron microscope (SEM). 

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