W31 Standard doped tungsten with excellent non-sagging property Applications: Filaments for bulbs lamp and fluorescents lamp. Heaters for electron tubes. Vacuum metalizing material and high temperature structural material. all kinds of W31 doped tungsten: Type: finishing diameter range D as drawing 0.3-3016 E Electrolytic Polishing 0.4-3016 ES Electrolytic Polishing and straightening 0.4-3016