Quality control points of ductile iron parts
2022-07-08
With the development of high strength and lightweight direction, the market of ductile iron parts is relatively getting bigger and bigger.The production of spherical iron thin small pieces should control its can not occur white mouth, hard edge, the solution: (1) control the chemical composition (2) increase the pouring gate, (3) the baked iron liquid temperature> 1450℃, improve the pouring temperature.Ball iron thick large fill and shrinkage outlet, casting cooling is slow, easy to produce spherical decline, shrinkage loosening and graphite floating, often single casting test rod qualified, casting body has shrinkage loosening or gold unqualified.Solution: Remove or shrink the shrinkage opening.Place the local or most of the cold iron.The production of spherical iron from the casting process, chemical composition and spherical control of the experience.First, casting process: one, the casting principle classification surface as far as possible the main cavity in the bottom box, conducive to the process design, sand box rigid strong sand to eat less, balanced solidification, thick with direct cold iron or sand separation cold iron, accelerate cooling to get qualified organization.The design principle of pouring system is fast pouring, slag retaining, filling and shrinkage, economy and easy to clean up.The shape of the inner pouring is better (rectangle or approximate square), easy to shrink and the temperature difference is small.semicircle or triangular inner pouring port should not open poor shrinkage effect, semicircle or triangular pouring center insulation is strong, pouring center and casting joint easy to form a shrinkage hole.After filling solidification quickly improve the smoothness and internal density of the casting, no mouth to simplify the process saves the cost, the mouth as far as possible with dark pressure mouth easy to operate, if large parts can not be poured full must be manual fire (iron filling) effect is large.
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