3 c 9 25 463 3 d__________________________________________________________________________ d extremely uneven surface b acceptable but needs further improvement a smooth surface c uneven surface the data for samples no 1 to no 5 shows that the method of the present invention provides a highly uniform zn coating with good appearance even at a wire feed speed as high as 30 m min the advantages of the present invention are not lost on the other hand the data for samples no 6 to no 9 reveals that the appearance of the wire treated by the conventional method becomes worse as the wire feeding speed increases another disadvantage of the conventional method is that the graphite powder burned and produced a combustion gas that had to be discharged from the drawing apparatus this is not necessary with the method of the present invention a tin coating was formed on soft copper wires diameter 0 6 mm by the hot dipping method of the present invention using drawing apparatuses of the types shown in fig3 a and 5b as well as by the conventional method using a melt the surface of which was simply covered with a flux 34 azonile 34 manufactured by imanishi chemical co ltd of japan the drawing apparatus 6 shown in fig5 a and 5b used an inner pipe 5 having holes 17 through which a gas 10 was introduced the gas 10 was a cryogenic gas evaporated from liquid nitrogen the soft copper wires were degreased washed with.