Abstract
Penetrations of bead-on specimens (200×200 mm, 6, 10, 15 and 20 mm thick) of plain carbon steel were measured for, various welding conditions. (see Fig. 1 and Table 1).Penetration and bead width were presumed by theoretical calculation of temperature distribution near the weld. (see Fig. 2). These are shown-in Figs. 3, 4 and 5, where Q: heat input per unit time (cal/sec), λ: thermal conductivity (cal/cm.sec°C), k: temperature diffusivity (cm2/sec), θ1: melting temperuture (°C), W: width of'heat source (cm). From this calculation, penetration (d) and bead width (b) are expressed by equations (3) and (4). Constants m1, m2, n1, n2 and K are given in Table 3 for the typical electrode "A" in Japan. The change of arc length (or arc voltage) little affect the penetration as shown in Fig.7. The effect of welding current (I amp.) and welding speed (v cm/sec) on penetration is shown in Figs. 8 and 9 respectively. The effect of electrode size is shown in Fig. 10.
