The lubricant, which is soluble in water, which withstands high temperatures

摘要

PICT:0815355/III/1 A heat-resistant water-soluble lubricant suitable for high-temperature metal-working operations comprises a mixture of an alkali metal borate and an alkali metal phosphate but no oil, fat or gelatinous substance. The preferred composition consists of one part of sodium tetraborate and 5 to 20 parts of potassium phosphate. It may be applied as a melt, powder or aqueous solution. The graph shows the melting points of various mixtures which may be used. Prior art lubricants mentioned are oils, calcium soaps, metal suspensions, colloidal thorium hydroxide, vanadium hydroxide, aluminium powder, molybdenum sulphide, complex inorganic substances, e.g. incompletely dehydrated polyphosphoric or polyboric acid, and silicate glasses and glazes.