W-1 is used for making the pole, wire drawing, or doing steal-making additive. W-4 is used as the steal-making additives. The impurity content accords with GB3459-82. ElementsContent(%)MaxElementsContent(%)MaxFe0.005Mo0.01Ni0.002P0.001Al0.002C0.005Si0.002O0.002Ca0.003Mg0.002