CASTING CLEANING:-
The moulds should be broken at a temperature when no transformation occurs. For example, for ferrous alloys, breaking should be done below 7000C, for thin and fragile casting, it should be below 4000C and for heavier castings, it should be at 5000C.
The process of cleaning of casting is known as fettling. This includes removal of cores, gates and risers, cleaning casting surface, chipping of unnecessary projections etc. Dry sand core can be removed by knocking off with iron bar, by means of core vibrator or by means of hydro blasting. The selection of the method depends on the size, complexity and core material used.
The gates and risers can be removed by hammering, chipping, hack sawing, abrasive cut off and by flame or by arc cutting. For brittle materials like grey cast iron, it can be done by hitting with hammer. For steels and other materials, sawing with hacksaw or band saw is more convenient. For large size gates and risers, flame or arc cutting is used. Similarly for removal of gates, abrasive cut off can be used. Fins and other small projections after removal of gates can be chipped off by using hand tools and pneumatic tools.
The moulds should be broken at a temperature when no transformation occurs. For example, for ferrous alloys, breaking should be done below 7000C, for thin and fragile casting, it should be below 4000C and for heavier castings, it should be at 5000C.
The process of cleaning of casting is known as fettling. This includes removal of cores, gates and risers, cleaning casting surface, chipping of unnecessary projections etc. Dry sand core can be removed by knocking off with iron bar, by means of core vibrator or by means of hydro blasting. The selection of the method depends on the size, complexity and core material used.
The gates and risers can be removed by hammering, chipping, hack sawing, abrasive cut off and by flame or by arc cutting. For brittle materials like grey cast iron, it can be done by hitting with hammer. For steels and other materials, sawing with hacksaw or band saw is more convenient. For large size gates and risers, flame or arc cutting is used. Similarly for removal of gates, abrasive cut off can be used. Fins and other small projections after removal of gates can be chipped off by using hand tools and pneumatic tools.
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