已经有次观看 wencong在2013-07-08发布

Channel：Tungsten 标签： Tungsten 

简介：Tungsten, a metallic element. Atomic number 74, atomic weight 183.85. Steel gray or silvery-white, high hardness, high melting point, room temperature from air attack; mainly used for manufacture of the filament and high-speed cutting steel, hard mold, also used in optical instruments, chemical instruments. China is the world's largest tungsten storage power.