Welding amplitude

In linear vibration welding, the surfaces to be joined are rubbed together in an oscillating, linear motion under pressure applied at a 90° angle to the vibration. Process parameters are the amplitude and frequency of this motion (weld amplitude and weld frequency), weld pressure, and weld time, all of which affect the strength of the resulting weld (Fig. 14.28). 

Figure 14.28 Linear vibration welding. Part surfaces are rubbed together in a longitudinal direction, along the z axis, generating heat through friction. Processing parameters are the weld amplitude, a, the weld frequency, n, the weld pressure, p, and weld time, f. Pressure is applied along the y axis, 90° to the vibration.

No emission during holds was observed but the concentration of events in clusters and the high level of amplitude of events confirmed the results of the proof test. After 20 bars, the bottom of the vessel around the defect became silent and activity is observed in the high part of the vessel near welds. 

The exact position of reflectors within the weld volume is calculated by means of the known probe position plus weld geometry and transferred to a true-to-scale representation of the weld (top view and side view). Repeated scanning of the same zone only overwrites the stored indications in cases where they reach a higher echo amplitude. The scanning movement of the probe is recorded in the sketch at the top, however, only if the coupling is adequate and the probe is situated within the permissible rotation angle. 

Figures 5 presents the results of scanning of the same section of a welded joints with approximately one year interval. Figures 6 shows the same section in the mode of representation of the amplitudes of UT signals reflected from discontinuities in the...

Figs. 7 and 8 respectively show the ripples obtained by SIMS and neutron reflection during welding of HDH/DHD interfaces. Its interesting to note that all dynamics models predict ripples since in general, the chain ends move faster than the chain centers. However, their shape, amplitude and time dependence provide a... 

Fig. 2.16 SQWVs for silk fibers pigmented with (a) granado (b) alazor, (c) curcuma, (d) weld, and (e) cochineal red in contact with acetic/acetate buffer (total concentration 0.50 M) at pH 4.85. Potential step increment 4 mV square wave amplitude 25 mV frequency 5 Hz...

Fig. 2.20 SQWVs (first scan) of weld (a, b) and logwood (c, d) immersed into 0.25 M HAc + 0.25 M NaAc (a, c) and that electrolyte plus 0.05 M AICI3 (b, d). Potential step increment 4 mV square wave amplitude 25 mV frequency 15 Hz [124]...

To investigate the control factors of welded component s fatigue behaviour, and use the analytical methods for estimating the total fatigue life of welds subjected to variable-amplitude loading histories and surface treatments, in order to find some possible methods to improve the fatigue strength. 

Scorim Process or SP (Cinpres-Scorim), Rheomolding Process or RP (Thermold s), and the Press Alpha Process or PAP (Sumitomo Heavy Industries and Sankyo Chemical Engineering of Japan) processes are examples of this method. The SP multi-live feed molding process where two packing pistons oscillate 180° out of phase and eliminate weld lines, etc. The RP system provides 3-D orientation based on the concept of melt rheology as a function of vibration frequency and amplitude as well as temperature and pressure. The equipment utilizes piston/type melt accumulators set up adjacent to the melt stream of the plasticator. Piston oscillates back and forth. The PAP system uses compression pins that are... 

It can be seen that for an increased frequency, but at the same intensity level, the maximum amplitude motion decreases, but this is accompanied by a dramatic increase in acceleration. This is an important parameter when considering the chemical effects of ultrasound. This type of measurement is also of great interest in welding and drilling systems. In principle, according to Eq. (2), this permits the calculation of the sound intensity. Unfortunately unless it is known how much of this motional amplitude is transmitted to the sonicated medium it is again difficult to correlate this value to the actual transmitted power. Furthermore, for a given amplitude, the effect of ultrasound depends on the surface area of the emitter immersed in the medium. 

Mechanical vibration of the drive armature is transferred along the attached spring rod, through a welded node point to the probe. The probe is driven into mechanical vibration at the same 120 cps frequency. The amplitude of the vibration of the probe depends upon the viscosity of the process medium. 

Resistance to microfissuring is strongly affected by plate structure it is excellent in a plate with fine and fibrous structure, as shown in Fig. 1. Because of severe safety requirements for LNG storage tanks, the quality of the majority of welds is specified to be monitored by ultrasonic inspection. The accuracy of ultrasonic inspection of weld defects depends mainly on the ultrasonic characteristics of the base metal, in which noises and attenuations are important. Distance amplitude correction curves, obtained in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code and NV Rules, are shown in Fig. 1. Since the evaluation level is 20% of the reference level (R.L.), it is difficult to detect defects unless the noise level is below 20% of R.L. at every node. Noises and attenuations of ultrasonic responses increase with coarsened plate structure, and in plates with very... 

The importance of adequate calibration is paramount in any ultrasonic inspection and is generally caurried out both to monitor equipment stability and to enable defect echo amplitudes to be referred to those from known standard reflectors. Figure 6 depicts the calibration block specifically designed for this work. One surface was machined concave with the same radius of curvature.as the cone at the position of the outer weld. Two 3 mm diameter flat bottomed holes (FBH) and a 1.5 mm diameter side drilled hole (SDH) were provided at a depth equivalent to the cone plate thickness and spaced sufficiently far apart that reflections could be obtained from each one independently of the others. A second 1.5 mm SDH at 15 mm depth served two purposes, firstly as euti equivalent reflector to the SDH in the standard A2 block and secondly to provide a means, in conjunction with the other SDH, of checking the probe angle. One section of the block, V thick, simulated the cone plate itself and was used for recording backwall echo amplitudes for the focused and normal probes. 

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