Ceratizit India Pvt. Ltd. Offers Special Tungsten Carbide Knives. Ceratizit India Pvt. Ltd is an ISO 9001:2000 certified company. Special Tungsten Carbide Knives are used for the paper, plastic and metal industry. They are made from solid tungsten carbide, TCT, powder metal, or HSS. Special Tungsten Carbide Knives are used as rotating cutting tools, milling tools for rotating cutters and book binding.