tungsten Carbide valve core,valve seat HRA>91.5 TRS> 2600 Grain size 0.5, ... tons of APT, 3, 000 tons of tungsten metal powder, 2, 000 tons of tungsten carbide powder, and 1, 500 tons of mixture ... of tungsten mining, ore dressing, smelting, and milling, In addition, it and has the right to operate import and export. tungsten Carbide valve core, valve seat ...