Heat transferred to the base metal in arc welding was measured by using two plate widths, namely 35 mm and 11 mm, and the writers attempted to separate the heat into two component parts, one being transferred to a comparatively wide surface of the plate, and the other being delivered to the crater.
As both the melting speed of welding rod, and the heat absorbed by the base metal are proportional to the welding current, the heat absorbed can be expressed by equivalent voltage.
For example, in case of Shinko B-17 welding rod, when the arc voltage is kept 30 V, total heat absorbed by the base metal is 23.5 V (78%) and 18.5 V (62%), width of plate being 35 mm and 11 mm respectively, while heat delivered to the crater was estimated to be about 16.3 V (54%) (See Fig. 11, Fig. 12, Fig. 17.)
Some discussions are given on the papers of Rosenthal (1-2) and also Naka (15-17) on the thermal efficiency of welding arc.
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