... Standard:GB 4187-842.Model number:W1,W23.Purity:99.95%1.Chemical composition: GradeTungsten contentContents of Impurity ElementsTotal ContentContent ... , heater and the electronic mechanical engineering, etc.Tungsten rod can be used in making the electricity photo source, ... the automobile and the tractor light bulb, make lattice side rod, framework, leading wire, electrode, heater and contact materials ...