First the welding current and voltage waveform was analysed by the waveform analyser containing a microcomputer. Then the correlation between waveform data and arc stability was im estigated. When ...welding current is low, the standard deviation of an average current in a short circuit duration and the average interval between short circuits, etc. correlate-well with arc stability. But when the current is increased, these correlations become poor. From the results of multiple regression analysis about waveform factors and arc stability, four factors which correlate well with arc stability were selected. A general index for arc stability which uses four factors was established. In the welding tests under various conditions, this index was shown to be capable of differentiating between stable and unstable arc.
Some effects of welding conditions on the strength of spot welded joints were studied. Spot welds under various welding conditions were performed on SPC-1 (cold rolled carbon steel sheets). Static ...tensile and bending fatigue tests were carried out, and the following results were obtained: (1) A dominant facto: on bending fatigue strength was different from that of static tensile fracture strength. The static tensile strength increased with nugget diameter. The bending fatigue strength changed with HAZ angle (θ), which is the angle between the heat-affected zone and the plate surface. (2) It was found that the fatigue crack propagated along the parallel direction to heat-affected zone. (3) The welding condition of R.W.M.A. class A gave the maximum static tensile strength but the minimum for bending fatigue strength.
This paper describes the optimum YAG laser welding conditions applied to the manufacturing of a workless on magnet print wire matrix head. The relation between the YAG laser welding conditions and ...metal structures is clarified. Furthermore, the effects of laser power, amount of defocus and heat treatment temperature are examined in relation to mechanical welding strength. The resulting optimum welding conditions are summarized as follows: laser power is 2.5-5 J, heat treatment temperature is 150-200°C, and the amount of defocus is ±1mm. With these conditions, a welding strength of over 100 N is obtained. The printing head weight is reduced to about 40 g and life is increased to over 107 printing times. This means that the weight is one-fifth and the life is twice that of previously reported printing heads.
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