Effect of water temperature on the non-crystallinity of FeSi_7.5B₁₅ (at%) wires produced by the in-rotating-water spinning method

The effect of water temperature on the shape, cooling characteristics and non-crystallinity of FeSi_7.5B₁₅ (at%) wires produced by the In-Rotating-Water Spinning Method was examined experimentally. The nozzle diameter was 0.25 mm and the incidence angle of molten metal jet to the water surface was 60°. The drum rotational velocity v_d ranged from 5.8 to 8.5 m/s and the jet velocity v_j from 5.9 to 9.5 m/s. The water temperature T_w was set at 283, 303 and 323 K. The wire produced at T_w≈283 K showed a smooth surface. At T_w≈303 K, a structure like a string of beads appeared partly on the wire surface. At T_w≈323 K, the wire looked like a string of beads. A straight wire was obtained for v_j/v_d≤1. The wire became meanderous with increasing v_j/v_d for v_jlv_d>1. The jet temperature decreased almost linearly with the distance from the point of incidence and it's value was higher for higher V_j. The average cooling rate of the wire in the temperature range of 1470 to 1200 K was lower for higher T_w. It decreased gradually with decreasing v_d and increasing V_j. For a constant T_w, the heat of crystallization ΔH, which is a parameter expressing the degree of non-crystallinity of the wire, was uniquely dependent on the v_j/ v_d ratio. For 0.7<v_d/v_d<0.97, ΔH showed a high value which was almost independent of T_w. For 0.97<v_j/v_d, ΔH decreased with increasing v_j/v_d and the decrease was more significant for higher T_w. However, a definite correlation was not observed between the measured cooling rate and ΔH. Discussion was made of the factors that affected the non-crystallinity of the wire.