Method of reducing leaching of cobalt from metal working tools containing tungsten carbide particles bonded by cobalt

摘要

Metal-working compositions (water-base, oil-base and oil-in- water emulsions) containing triazole and thiadiazole compounds are disclosed. These compositions prolong the working life of metal cutting and grinding tools containing tungsten carbide particles bonded together by nickel or cobalt. The oil-base coolant and lubricant comprises a mineral oil, a triazole or thiadiazole compound, and optionally, an extreme pressure lubricant, fats, rust preventives and mist suppressants. The aqueous base and oil-in-water emulsion metal-working compositions are prepared in the form of a liquid concentrate which subsequently is diluted with water to form the metal-working coolant or lubricant. The concentrate to be diluted and made into an aqueous coolant and lubricant comprises a triazole and thiadiazole compound, boric acid, an amine or mixture of amines, sodium gluconate and an aromatic or paraffinic carboxylic acid. Optionally a wetting agent, bactericide, fungicide, extreme pressure agent and an antifoaming agent can also be added to the formulation. The concentrate to be diluted to form an oil-in-water emulsion lubricant and coolant comprises mineral oil, a triazole or thiadiazole and emulsifiers. Optionally, there may also be added bactericides, extreme pressure agents and antifoaming agents.