Seeder

SeederCHARACTERISTICS AND FEATURES: Seeder is a product in granular form used as an inoculant for treatment of cast iron melts in ladle. When the molten cast iron is treated with Seeder, the chill is reduced and improvement in mechanical properties as well as machinability is observed. Inoculation is necessary for the production of sound casting with uniform mechanical properties through out the section. Seeder is a product which has been developed after long experience and experimentation in many foundries and is a granular mixture of graded and balance inoculating materials.METHOD OF USING: Seeder should be added to clean molten metal. The best way of inoculation is to add Seeder in the stream of metal as late as possible. Accuracy in adding is essential since it is harmful to over-inoculate as well as to under inoculate. Over inoculation increases shrinkage and porosity in susceptible castings. ADVANTAGES: Reduction in Chill: Effect of inoculation is generally checked by chill/wedge test and tensile test piece. Chilling tendency is assessed by fracturing and measuring the width at a point where chill ceases. Un-inoculated flake graphite iron, especially those with low carbon equivalent are more prone to chill in thin sections, corners, sharp edges etc. Seeder treatment reduces chill tendency. Promotes A type of Graphite: Un-inoculated iron (with low carbon equivalent) is likely to contain under cooled graphite known as 'D' and 'E' type graphite. Under-cooled graphite affects the strength, and machining properties. When molten metal is treated with Seeder, the inoculation effect will eliminate under-cooled graphite and promote formation of 'A' type graphite to give better mechanical properties. Improves Microstructure: Un-inoculated cast iron many times show, to a great extent, difference in graphite structure and ratio of Ferrite to Pearlite, between thin and thick sections. Thin sections tend to contain fine graphite and free ferrite which reduces tensile strength. Thick sections tend to have coarse graphite which also reduces tensile strength. Seeder treatment ensures uniform graphite structure and promotes formation of pearlite and hence improves mechanical properties. Action of Seeder lnoculant: Inoculation in short is a method of controlling the form and distribution of graphite in iron during solidification. Inoculation treatment increases the number of nuclei in the molten cast iron and therefore, creates a large number of eutectic cells. As the eutectic cell count increases the flake size becomes smaller. Inoculation refines grain size and promotes the formation of 'A' type graphite. PRODUCT SELECTION: The choice of grade of inoculant will depend on the metal composition, section thickness of casting, charging materials, melting temperature, and also ladle size etc. Some of the grades are given belowSeeder-1:- Very good inoculants for high steel charge mix in cast iron. Chilling tendency is reduced in thin sections. Ideal inoculant for auto castings and thin section castings. Seeder-10:- Gives more consistent results over a wide range of iron compositions. It has longer fading time. Seeder-12:- Economical grade of inoculant which reduces chill and increases machinability. Seeder-35A:-More effective for automotive castings, when induction furnace is used as the melting unit. SUGGESTIONS FOR ACHIEVING BETTER RESULTS: Seeder should be stored in a dry place. Briefly stir the inoculated iron. Do not inoculate cold iron. Add inoculant only after removal of slag. Grey cast iron responds more favorably to inoculation if its sulphur content is in the range of 0.05-0.15% provided adequate Manganese is present to prevent formation of iron sulphide. MODE OF STORAGE: Keep in dry place and away from moisture. SHELF LIFE: One year from date of manufacture. MODE OF PACKING: 50 kg. Polythene lined gunny bags