Abstract
Temperature cooling rate is calculated for points near bead line in thick plate when linear heat source is applied instantaneously along all the range of bead whose length is l. Fig. 4 shows CR (cooling rate passing a definite temperature Ts) along the bead, and we see that CR at bead end is 2 times the bead center of infinite length. For the point whose distance from the bead end is 2 times rm, CR is 0.56 times the bead end. Here rm means the perpendicular distance from the bead, where the maximum temperature is equal to Ts, and rm is shown in equ. (29). Equ. (4) gives the relation of CR and temperature Ts, input heat q0.
Fig. 7 shows the effect of bead length, and we see that for l>2rm, CR for the bead end is practically equal to that for l=∞, and for l<1.5rm, CR is equal to that of the point heat whose heat is equal to q0⋅l.
For a moving point heat source, cooling rate is also calculated for starting and stopping ends of bead and those values are compared with that of infinite velocity. From Fig. 8 we see the ratio tends to unity for X>10.
