... tungsten Carbide valve core,valve seat HRA>91.5 TRS> 2600 Grain size 0.5, 0.6, 0.8 high quality wearability and ... 3, 000 tons of tungsten metal powder, 2, 000 tons of tungsten carbide powder, and 1, 500 tons of ... and technology enterprise capable 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 ...