News
Mold in the home appliances, automotive, electrical, aerospace and other industrial areas has increasingly become the main process of industrial production, the main process equipment, and bear the 60%-90% of these industries in the production of parts and components of the processing. In recent years, high speed milling has broken through the limitation of traditional milling hard, high strength and high toughness die materials. But electric discharge machining with high machining accuracy and surface quality, wide processing range, especially in high speed milling can match in the advantage of joints, high hard materials of the mould cavity machining of complex and precise, thin-walled, narrow, so in electrical discharge machining (EDM) will still be the main means of the mold cavity…
Graphite crucible is widely used in casting but many customers don’t know how to use it correctly. It is very significant for a new made graphite crucible to be conditioned before it is used. Using a graphite crucible correctly includes conditioning and storage. The crucible should be put in an oven at 500 degrees Fahrenheit (260 degrees Celsius) for two hours and then allowed to cool slowly in a dry situation. This keeps moisture from the crucible and prevents cracking. Crucibles should be kept away from moisture and should be re-conditioned if they get wet. A graphite crucible should be cleaned completely when it is done being used. Metal should not be allowed to remain in the crucible to cool.…
Colloidal graphite was first obtained by Acheson in nineteenth Century. Raw materials for natural graphite or artificial graphite. There are two methods for producing colloidal graphite: (1) mechanical method. Natural graphite crushed by hydrochloric acid and hydrofluoric acid to remove impurities. Added to the tannic acid in aqueous solution by repeated decantation into paste. Adding a certain proportion of water and ammonia, and then by ultrasonic treatment to further reduce the particle size, you can get colloidal graphite. (2) chemical method. After purification and crushing of natural graphite, adding concentrated nitric acid and concentrated sulfuric acid and water at 90 degrees Celsius, and then cleaning, drying, adding water, ethanol, acetone and other dispersing agent that is colloidal graphite. Addition of…
