Ceramic riser neck and sand mould structure capable of reducing defects of high-nickle nodular iron reaction layer

Abstract

The invention discloses a ceramic riser neck and sand mould structure capable of reducing defects of a high-nickle nodular iron reaction layer. The ceramic riser neck and sand mould structure comprises a wet mould lower sand mould, a wet mould upper sand mould, a casting mould cavity formed in the interface of the wet mould lower sand mould and the wet mould upper sand mould and a cladding assembly arranged in the casting mould cavity and further comprises a casting assembly, wherein one end of the casting assembly is positioned at the interface of the wet mould lower sand mould and the wet mould upper sand mould and communicates with the casting mould cavity and a cladding mould cavity; the other end of the casting assembly stretches out of the wet mould upper sand mould; and the claddingassembly comprises a cladding shell mould, a cladding sand core and a heat insulating riser. According to the ceramic riser neck and sand mould structure, on the one hand, during pouring, wet mould sand moulds, a precoated sand cladding shell mould, a cladding sand core and a heat insulating riser sleeve react with iron liquid to generate plenty of turbulent flow oxidized gas, and the turbulent flow oxidized gas can be conveniently discharged out of a second exhausting rod to reduce the reaction probability of gas and Mg in the iron liquid; and on the other hand, a ceramic riser neck is arranged at the bottom of the heat insulating riser to prevent influence of the turbulent flow oxidized gas to nodularization of casting at the riser neck, so that generation of defects of the casting reaction layer at the high-nickle nodular iron riser neck is effectively reduced.

Description

technical field [0001] The invention belongs to the field of mechanical casting, and in particular relates to a ceramic riser neck and a sand mold structure for reducing the defects of the high-nickel nodular iron reaction layer. Background technique [0002] Cladding casting is to place the shell mold of the casting structure, the inner cavity sand core and the thermal insulation riser (capsule core) in the mold cavity of the green mold sand molding, and its main gating system and exhaust system are composed of damp Mold sand molding is formed, and the upper and lower sand molds of the green mold are poured together to obtain high-precision and high-quality castings. Shell casting is actually a form of shell casting. Clad casting combines shell mold casting and green sand casting together, and is suitable for mass production of automatic molding lines. At present, it is widely used in domestic and foreign foundry industries. It is generally used in small and medium-sized c...

AI Technical Summary

Problems solved by technology

[0006] The study found that the reasons for the defects in the high-nickel ductile iron reaction layer: First, the large amount of gas generated by the coated sand shell mold, sand core, thermal insulation riser or heating riser, etc., resulting in a large amount of turbulent oxidizing gas atmosphere, coupled with the molten iron The smelting process is severely oxidized, and the filling of the molten iron is not stable during pouring, resulting in a large burning loss of magnesium in the high-nickel molten iron, thickening of the flake graphite layer, and serious defects in the reaction layer; The membrane sand cladding and sand core contain a high amount of S, which is decomposed by heat to produce SO2 gas, which is adsorbed on the surface of the unsolidified casting, so that the S atoms diffuse into the molten iron, and at the same time, it is mixed with Mg, Fe, etc. Elements react to form sulfides, resulting in insufficient effective amount of Mg element in high-nickel ductile iron parts, resulting in flaky or non-spherical graphite on the surface of the casting

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